CORAL COLOR AND WHAT IS REQUIRED TO MAINTAIN IT

CORAL COLOR AND WHAT IS REQUIRED TO MAINTAIN IT by Orphek

Up to 90% of SPS coral's nutritional needs are obtained by the food produced by Zooxanthellae. These dinoflagellates are single celled algae that reside and grow within the coral’s tissue.  Several million of these algae cells live in just one square inch of a coral’s tissue. These microscopic algae use energy from sunlight to make food for the coral through photosynthesis.  This is accomplished by converting carbon dioxide into oxygen and carbohydrates (sugars). This process requires plenty of sunlight and is why coral colonies are only found in clear, shallow water. Hard corals are very dependent on Zooxanthellae and will not survive long without them.

 

The Zooxanthellae are also what determine more than 90% of a coral’s color.  Without Zooxanthellae, the coral’s tissue would appear white or translucent.  For a coral to maintain its colorful hues, correct lighting intensity and spectrum must be given to them.  In addition to lighting, different colored corals use different major and minor trace elements to maintain their coloration and these elements must be provided in our closed systems if we wish to continue to observe their colorful beauty.  Many reef aquarists have observed that after bringing home their beautiful pink Acropora, its color rapidly changed and this is due to lack of the proper elements needed to maintain the pink, or any other color for that matter.

 

We will identify the numerous elements and some of their benefits to corals.

• Iodine and Halogen – Two elements that promote the color in pink corals.


• Potassium and Boron – Promotes the red in red corals.


• Iron, Manganese, Cobalt, Copper, Aluminum, Zinc, Chrome and Nickel promote the green coloration in green corals.  These are all considered light metals and should not be confused with heavy metals.


• The above elements provide more than just color stability, but for this article we are just focused on maintaining our coral’s color.


• Amino acids – Amino acids consists of carbon, nitrogen, oxygen, and hydrogen.  Amino acids are important in nutrition as they serve as the building blocks for protein.  Amino acids cannot be created from other compounds and must be taken in as food or vitamin supplements.  Marine phytoplankton is a good food source that is rich in amino acids.

It must be understood that many of these elements are depleted quickly due to their high oxidative abilities and reactions with organic materials and removal by protein skimming and/or carbon and chemical filtration.  Therefore, they must be supplemented on a regular basis by doing weekly water changes with a good quality salt such as Seachem’s Aquavitro Salt and/or by using supplements specifically developed for coral coloration such as Red Sea’s Color Program.

 

A clean low nutrient tank also provides a vital role in the actual color of your coral.  Efficient protein skimming, controlled feeding, and bioload will all help significantly in increasing water quality.

 

Fortunately, the lighting problem is solved by the use of Orphek LED lighting systems which provide the ideal intensity and spectrum for maintaining good coral health.  As to the needed elements, there are several manufacturers that market these products. Red Sea, Tropic Marin, and Brightwell are highly recommended.

 

 

 

Accelerating Coral Growth

Accelerating Coral Growth in a SPS/LPS Dominated Aquarium By ORPHEK

One of the most popular questions on marine forums are “how can I get my corals to grow faster”.  How corals grow and multiply is very complex and is a science by itself.  What we will give you are the requirements SPS corals need for accelerated growth rates and no degree in Marine Biology is needed.

 

Corals form and grow skeletons by absorbing the elements they require from the surrounding water.  This process is called Skeletogenesis whereby the coral combines the water’s calcium and CO3 ions (carbonates) to form Aragonite (CaCO3).  Other minor elements are also needed and absorbed by the coral and these include calcium fluoride, strontium carbonate, calcite and other trace elements.  When these elements are not available in the correct ratio, a coral’s growth rate will be limited.  When elevated levels of these elements are in place, a more positive ionic pressure is created which allows the coral to more efficiently transport and relocate these elements into its tissue.  Low levels of magnesium and/or strontium will cause the skeleton to become more brittle and more easily damaged.  Low magnesium levels can lead to alkalinity drops which limits carbonates that are required for proper skeleton growth.

 

There are many products on the market claiming to provide the elements corals need to grow quickly.  Many of these products work well and some may be “snake oils” so it is best to research before investing money to ensure the product(s) you select are proven performers. Red Sea, Brightwell Aquatics, and Tropic Marin are likely the most popular companies that produce these products.  Many aquarists may prefer to dose these elements individually through dosing pumps operated by aquarium controllers.

To increase the growth rate of juvenile SPS/LPS corals, coral frags, and clams, Orphek recommends that you maintain the following water parameter levels:

Salinity – 35ppt (1.026)

Note:  Orphek recommends and uses Seachem’s Aquavitro salt.

pH – 8.0-8.3

dKH – 12.0-12.5

Calcium – 450-465ppm

Magnesium – 1370-1390ppm

Strontium – 8.5-10ppm

Note:  Multiplying your desired calcium level by 3 will give you the magnesium level needed for the proper balance between calcium and magnesium.

For those interested, a calcium/magnesium calculator by Euroreefers can be downloaded here. 

 

calcium magnesium calculator

It is very important to maintain these levels as stated above and this will require frequent testing until a proper dosing level is achieved.

Is that all there’s to it?  No, with pristine water quality and proper flow rates established, the paramount need is for proper lighting of the correct spectrum and intensity (PAR/PUR).  Orphek Power Reef and the DIF series of LEDs are specifically designed, tuned, and tested to meet the lighting requirements corals need to grow and thrive.

 

In our next blog we will discuss how to achieve good coral coloration.

WHY DO CORALS BLEACH

WHY DO CORALS BLEACH?

A BLEACHING SURVEY CONDUCTED BY ORPHEK

Orphek has recently conducted a bleaching survey and invitations were sent out to prominent, experienced aquarists, and to Arjen Tilstrea, a Marine Biologist.  The questions asked were:

1.          How long have you been in the marine aquarium hobby or research work?


2.          Which type or family of corals do you or have you maintained?


3.          Do you mix Euphyliids, Mushrooms and Zoanthids containing palytoxins (Genus Palythoa) with other coral?  If so, what size    aquarium are they in?


4.          What types of filtration (including protein skimmers/brand name and model) do you use?


5.          What are your preferred levels of salinity, pH, dKH, calcium, and magnesium?


6.          Do you employ automated dosers, and if so, what do you automatically dose?


7.          How often do you test your water and which tests do you perform?  What are your usual results?


8.          Which supplements do you regularly dose?


9.          With the exception of calcium, magnesium, and alkalinity buffers, which other supplements do you dose and why do you feel they are beneficial?


10. Do you regularly feed your corals, if so, what is your preferred food or foods?


11. Do you incorporate a refugium, algae scrubber, or DSB?


12. Describe your present lighting system in your display tank, brand, Kelvin temperature and photoperiod used.


13. Which brand(s) of salt and supplements do you prefer and why do you feel that that brand or brands are more beneficial than others?


14. Do you use aquarium controllers and/or electronic water testing equipment?


15. How often are water changes performed and what percentage?


16. Do you employ carbon dosing to control nitrates and phosphates, and if so, what method do you use.


17. Have you ever experienced coral bleaching in your aquarium(s)?


18. If yes to the above, what did you feel may have been the cause?


19. Were you able to reverse the process, and if so, how did you accomplish this?


20. What would you suggest to other aquarists to prevent coral bleaching?


21. What size is your display tank?

Before we begin, a short word about RTN (Rapid Tissue Necrosis) and Zooxanthellae (Symbiodinium).

Rapid Tissue Necrosis is often referred to as the “White Syndrome” and appears as white bands or patches of tissue loss which generally affects Acropora Corals.  RTN is a fast acting contagious condition where coral tissue sloughs off the skeleton of the coral.  A loss rate of up to 10cm per hour will result in the death of the colony in less than 24 hours, but this of rapid death is rare in our captive systems.  The only effective cure that Orphek is aware of is by removal of diseased colonies and fragment branches at least 26mm ahead of any affected area.  After cutting the diseased colony off, it is recommended to seal the cut with Cyanoacrylate glue (Super Glue).

Symbiodinium.  The Genus Symbiodinium is made up of the largest and most prevalent group of endosymbiotic dinoflagellates known to science.  These unicellular algae reside in the endoderm of tropical Cnidarians such as corals, sea anemones, clams, and jellyfish where they relocate products of photosynthesis to the host and in return receive inorganic nutrients.  They are necessary for coral to thrive and grow.

We will begin with a statement from Arjen Tilstrea, a Marine Biologist.

“From experience, I know that not many aquarists actually know what bleaching is. Bleaching is the loss of zooxanthellae and/or photo pigments, NOT the loss of coral tissue. Most aquarists call a white skeleton a bleached coral but it is not. When corals bleach they still have their tissue around their skeleton and can eventually die if they are not re-infected with new zooxanthellae. A coral can survive for a couple weeks in a bleached condition. I don't think aquarists can really point out what causes bleaching in their tanks because there are too many factors that can influence and induce bleaching (temperature, light, water flow, nutrients etc.). I have never experienced bleaching in my previous tanks, I have experienced RTN (rapid tissue necrosis) though.

Cheers,

Arjen (Arjen Tilstea, Marine Biologist)”
In response to the survey, contributors were; Tanne Hoffe, Adrian Flynn, and Moshe Gur Arie who together have a combined total of 42 years of experience growing corals.  Their responses to individual questions are compiled below.

Tanne Hoffe 

1. How long have you been in the marine aquarium hobby or research work?

About 22 years hobby, teaching/studying biology about 12 years.

2. Which type or family of corals do you or have you maintained?

SPS, LPS, soft corals, zoanthids, gorgonians. Nearly all photosynthetic

3. Do you mix Euphyliids, Mushrooms and Zoanthids containing palytoxins (Genus Palythoa) with other coral? 

 If so, what size  aquarium are they in?

In the past also zoanthids, but my angelfish do regard these as food, so I can’t keep these anymore. I do still keep mushrooms and       Euphyliids with sps etc. Tank volume now (total system) about 200 gallons, in the past I also did this in smaller systems, about 50 gallons. I use some activated carbon to decrease levels of toxins/terpenes.

4. What types of filtration (including protein skimmers/brand name and model) do you use?

Royal Exclusiv BK200, a few days each month some (1 coffee cup on 200 gal) activated carbon, iron based phosphate remover if needed (prefer small doses exchanged more often in order to avoid sudden changes in water chemistry).

5. What are your preferred levels of salinity, pH, dKH, calcium, and magnesium?

Sal: 1.025, pH: 8.3, KH: 6-8, Ca: 420, Mg: 1300

6. Do you employ automated dosers, and if so, what do you automatically dose?

Yes, Balling salts as needed (1 vessel NaHCO3, 1 vessel calcium chloride, magnesium chloride, strontium chloride in ratio  as needed) and trace elements (Grotech Corall ABC, 2-3  ml daily). This is easier than dosing by hand, but most important, levels are much more consistent, as the doser splits up the set amounts in 12 separate dosings spread over the day.

7. How often do you test your water and which tests do you perform?  What are your usual results ?

About 3 times each month.  Results: Ca 400-420, KH 6-8, Phosphate: 0,03 or less, nitrate: about 1 mg/l.

8. Which supplements do you regularly dose?

See q. 6. Also, I do dose some amino acids (KZ, about 2-3 drops 2 x each week),
KZ Spongepower (about 2-3 drops 2 x each week), KZ kaliumjodidefluoride (about 2-3 drops 2 x each week)

9. With the exception of calcium, magnesium, and alkalinity buffers, which other supplements do you dose and why do you feel they are beneficial?

See q. 8. Amino’s: I THINK I see positive results in the corals, Spongepower: I see increased recover in damaged
corals and I see positive results in Goniopora’s, kaliumjodidefluoride: increased blue/purple colouration in sps, mainly in   Acropora and Montipora.

10. Do you regularly feed your corals, if so, what is your preferred food or foods?

A few times each month, I use FaunaMarin Ultramin F, Ultramin S and Ultraclam in a mixture. I see positive results in the coral’s health, mainly in LPS corals. The corals probably also catch some fish food every now and then.

11. Do you incorporate a refugium, algae scrubber, or DSB?
No.

12. Describe your present lighting system in your display tank, brand, Kelvin temperature and photoperiod used.

2 x Orphek Nilus  (9.00-11.00: low percentage, 12.00-20.00: 100%, 20.00-0.00: dimming to 10%, dark at night)
1 x Orphek PR156 (11.30-21.30: white and blue leds, 10.00-22.00 only 4 blue leds).

The combination of HQI with fluorescent (T5) was my preferred combination for the last 17 years, but both on the aesthetic and on the biological side, I am very happy to have switched to Orphek led (not to mention the electricity bill…). The tank improved a lot since I made this switch!

13. Which brand(s) of salt and supplements do you prefer and why do you feel that that brand or brands are more    beneficial than others?

Reef Crystals Salt as main salt, sometimes I use some other brands (mainly KZ Reefer’s Best) as well. RC is my preferred
salt as I’ve never seen any reverse reactions the last 15 years I use it, I have seen negative reactions with some other brands.

14. Do you use aquarium controllers and/or electronic water testing equipment?

Controllers/testers: timers, automated top off, ORP meter, thermometer, automated chiller.

15. How often are water changes performed and what percentage?

About 2 x each month, about 17% each time.

16. Do you employ carbon dosing to control nitrates and phosphates, and if so, what method do you use ?

In the past I did try some methods, but the tank consumes all nitrates. Phosphates are removed with iron based absorber if needed.

17. Have you ever experienced coral bleaching in your aquarium(s)?

Yes.

18. If yes to the above, what did you feel may have been the cause?

It was a very nice pink Stylophora pistillata which I put straight
under a 150 W hqi-bulb, next to some very nice blue and purple Acro’s which did great in that spot. I left it there for about a
month (went on holiday…) and all tissue receiving direct light was either bleached or dead.

19. Were you able to reverse the process, and if so, how did you accomplish this?

Move the coral to a darker spot stopped the bleaching, recover took long as algae already covered the dead branches.

20. What would you suggest to other aquarists to prevent coral bleaching?

Know the needs of your corals and take time to observe
reactions when placing or moving corals. Keep water parameters at safe levels and use bulbs of the right spectrum and intensity.
Lots of current help the coral with its metabolism, so this helps as well. If corals are kept in a very nutrient poor (ULNS) system,
try to ensure the coral gets ‘food’ by some means, for example make sure you stir op detritus every now and then, of make sure
the coral can catch bacterioplankton (for example: zeovit-like filter or biopellets in fluidized bed-filter). Otherwise, add fine food and/or feed the fish a lot. In my experience, many people underestimate the amount of food their fishes need (and their system can handle). Another way of keeping the coral’s health safe in a (very) nutrient-poor system is to add amino acids or nitrates so the coral can use these for their zoöxanthallae’s metabolism.

Some successful German coral farmers aim for ‘zero’ phosphates, but top the nitrates up to 10-15 mg/l! I do feed the corals directly, but I don’t need a lot of food. I am able to keep about 40 fishes in my 200 gallon  system without taking extreme measures to keep the water quality high.

All fish are well fed (including 4 tangs, 3 angels, 8 anthias…) and the corals thrive as they use the waste products of the fish as their food source. It’s all about keeping a healthy balance in input/output/metabolism in the ecosystem  of the system. Understanding the biochemistry of your tank helps a lot to prevent problems! Also, try to avoid sudden changes in the water chemistry, even if the changes are having a positive influence ‘on the numbers’ give the animals time to adjust. Corals from the reef flat often are exposed to sudden changes (rain, tides) in nature, but corals from water deeper than say 2-3 meters often have problems with rapid changes.

21. What size is your display tank?

Display tank is 190 gallons(gross), with a sump of about 40 gallons (net) and a small species tank tied to the system of about 7 gallons.

Tanne Hoffe aquarium

Adrian Flynn

1.          How long have you been in the marine aquarium hobby or research work? 10 years in the hobby.


2.          Which type or family of corals do you or have you maintained? Mostly SPS for the last 5 years.


3.          Do you mix Euphyliids, Mushrooms and Zoanthids containing palytoxins (Genus Palythoa) with other coral?  If so, what size aquarium are they in? No, my system is SPS dominant. I found the more lps and softies I had, the more problems I had with the sps…assume chemical warfare by the non-sps corals. My system volume is 2500L   


4.          What types of filtration (including protein skimmers/brand name and model) do you use? 2x ReefOctopus Extreme 5000 skimmers, huge ATS 1.2 x 1m, DSB which is 241 kilos of sugar fine aragonite, 500 kilos of live rock, chaeto that has its own cube 80x60x60


5.          What are your preferred levels of salinity, pH, dKH, calcium, and magnesium? Salinity 1026sg, pH 7.8-8.1, dKH 7, calcium 410ppm, and magnesium 1300ppm


6.          Do you employ automated dosers, and if so, what do you automatically dose? Yes but only to supplement the shortfall of my CARX unit, I add sodium carbonate and calcium chloride which I prepare myself.


7.          How often do you test your water and which tests do you perform?  What are your usual results. Sometimes twice a day for alk, only because if I see my carx drip rate is off, otherwise a must weekly. I test for dKH, calcium, and magnesium.  Results as per point 5.


8.          Which supplements do you regularly dose? Lugols Iodine, after lights out 12 drops…that’s it.


9.          With the exception of calcium, magnesium, and alkalinity buffers, which other supplements do you dose and why do you feel they are beneficial? As per point 8, my skimmers will remove this element, it’s the most volatile in terms of shelf life within your tank. So must be dosed daily. Also my chaeto and ATS removes a lot of this element, coral color suffers if low…can see it in montipora, first sign they go dull color, extreme is burnt tips in some sps.


10. Do you regularly feed your corals, if so, what is your preferred food or foods? Never had the need nor saw the value if I added or stopped….My belief is u simply adding more nutrients to your tank. I believe in feed fish heavy, their poop dissolves and that fuels the coral with what they need to eat.


11. Do you incorporate a refugium, algae scrubber, or DSB? Oh yes all three, and biggest I could possibly fit in.


12. Describe your present lighting system in your display tank, brand, Kelvin temperature and photoperiod used. I use sunlight and LED….4 Orphek 18K DIF100XP’s. on at 10am off at 9pm


13. Which brand(s) of salt and supplements do you prefer and why do you feel that that brand or brands are more beneficial than others? I uses Seachem Reefsalt, and Tropic Marin Lugols Iodine. I take what ever is cheap for me and Seachem does the job well.


14. Do you use aquarium controllers and/or electronic water testing equipment? I have a Profilux ex3…though I’m not using it close to its potential!


15. How often are water changes performed and what percentage? Weekly about 5% = 120L for my 2500 volume


16. Do you employ carbon dosing to control nitrates and phosphates, and if so, what method do you use. Used to…stopped for a long while now…tank looks better without. I run Rowaphos as well, but really don’t need to as my Hanna Checker tested a perfect 0.00ppm, BEFORE me adding the Rowaphos. Chaeto does the best phosphate remover job ever.


17. Have you ever experienced coral bleaching in your aquarium(s)? I came close when I started with by sunlit project as I was not aware of the power of the sun, I now use 40% shade cloth and even in peak summer corals do get stressed. Because of the sun using halides or LED, these have never been a danger to me as their PAR output is nothing close to the sun on a clear noon day!


18. If yes to the above, what did you feel may have been the cause? Excessive par (1000+) by the sun, coupled by high water temps 29+ degrees centigrade.


19. Were you able to reverse the process, and if so, how did you accomplish this? Yes, add shadecloth and move coral to shadier spot.


20. What would you suggest to other aquarists to prevent coral bleaching? Understand the light that coral was under, when changing your light unit to a new one. Coral placing (depth) is also important. Simply raise/shade the coral to acclimitize


21. What size is your display tank? 2000mm X 1000mm X 67mm (height) 

Adrian Flynn aquarium

 Moshe Gur Arie

1. How long have you been in the marine aquarium hobby or research work? It's my fifth year.

2.  Which type or family of corals do you or have you maintained? All types (soft, LPS, SPS).

3. Do you mix Euphyliids, Mushrooms and Zoanthids containing palytoxins (Genus Palythoa) with other coral?  If so, what size aquarium are they in? Yes, my tank is 200X70X60 cm – L,W, H.

4. What types of filtration (including protein skimmers/brand name and model) do you use? The protein skimmer is Deltec SC-2060, occasionally mechanical filtration with a 200 micron bag but generally without.

5. What are your preferred levels of salinity, pH, dKH, calcium, and magnesium? SG – 1.025, pH – 8.3-8.5, dKH – 8, calcium – 410, magnesium – 1300.

6. Do you employ automated dosers, and if so, what do you automatically dose? Only for the alkalinity.

7. How often do you test your water and which tests do you perform?  What are your usual results. I do most of the tests once every 2 weeks. These are the 5 main ones: Nitrate, phosphate, calcium, alkalinity and magnesium. My nitrate is usually 20-40 ppm and the phosphate is 0.3 ppm. The high values are because of too many fishes in the tank… There are 40 (I love to see fishes in my tank along with corals).

8.  Which supplements do you regularly dose? Alkalinity, calcium, magnesium.

9.  With the exception of calcium, magnesium, and alkalinity buffers, which other supplements do you dose and why do you feel they are beneficial? I was advised to put Lugol's and I dose 4 drops 3 times a week. I don't dose other supplements.

10. Do you regularly feed your corals, if so, what is your preferred food or foods? I feed my corals with my fishes and lately started to use a new special coral's food that was developed in my country (Israel) in a coral's farm.

11. Do you incorporate a refugium, algae scrubber, or DSB? Only macro algae in my sump.

12. Describe your present lighting system in your display tank, brand, Kelvin temperature and photoperiod used. I use 3 Orphek Nilus 18000K. They start gradually from 09:00 (10%, blue only) to 23:00 (40%, blue only). Full light (100% white + 100% blue) is between 14:00 and 20:00.

13. Which brand(s) of salt and supplements do you prefer and why do you feel that that brand or brands are more beneficial than others? I use Royal nature salt (made in Israel). I have no answers to the rest of the questions.

14. Do you use aquarium controllers and/or electronic water testing equipment? Yes, I use the Seneye Reef but only in the last month. However, I have controllers for temperature, for the water level and for the wave makers (Vortech).

15. How often are water changes performed and what percentage? I perform 2.5% water change each week. I do it by taking out water through the skimmer. This way is in the last 3 months only.

16. Do you employ carbon dosing to control nitrates and phosphates, and if so, what method do you use. I use the biopellets in a reactor.

17. Have you ever experienced coral bleaching in your aquarium(s)? Yes.

18. If yes to the above, what did you feel may have been the cause? It's hard to tell but it looks like parasites most of the times. There are times that I have 2 of the same coral's family on the same rock and very close to each other, one is in full flourish and the other one is bleached out. Also, moving coral can cause a stress that leading to bleaching.

19. Were you able to reverse the process, and if so, how did you accomplish this? Sometimes I cut the good part and it survives.

20. What would you suggest to other aquarists to prevent coral bleaching? I have no idea.

21. What size is your display tank? 850 liters(about 220G).

Moshe aquarium

From this brief survey we can see that:

All respondents have a relatively large aquarium.

All incorporate very good and efficient protein skimmers.

All keep calcium, dKH, and magnesium at very close to the same levels.

Only one respondent had a bleaching issue with one coral.

And MOST importantly, all respondents use Orphek high PAR/PUR LED Lighting which provides the ideal spectrum that corals best respond to.

We can see from the above information that one of the best ways to reverse coral bleaching is by using lighting of the proper intensity and spectral curve that corals respond to and Orphek LED lighting can and will provide this.  If other lighting technologies are used, lamp replacement will usually reverse this effect. If you are using the proper lighting and photoperiod, look at your water parameters and adjust if necessary.  Since most species of corals we keep produce 90% of the food they require, lack of phytoplankton or other coral foods is rarely an issue.

Orphek is aware that it would be difficult to pin point any root cause for bleaching based on four responses, so Orphek would like to invite you to respond to this survey.  Your responses will be posted in the comment section of this blog.  Your valued input will aid in making reef keeping more successful. 

UNDERSTANDING CALCIUM AND ALKALINITY

UNDERSTANDING CALCIUM AND ALKALINITY

By Orphek 

Understanding water chemistry can be one of the most frustrating aspects to new or seasoned aquarists alike without a formal education on calcium and alkalinity and how they can affect each other.  Most hobbyists do not like to read scientific writings about water chemistry or look at scientific equations ([SiO(OH)₃⁻] + H⁺ → [Si(OH)₄⁰]) depicting such and not understand what they are even looking at or reading about.  Orphek will attempt to simplify marine water chemistry in this article.

Stable and consistent levels of calcium and alkalinity not only insure growth of calcareous invertebrates, but also are required for their survival in both the ocean and our captive systems.  Coral, coralline algae, and animals with shells are made up of more than just calcium; they also contain carbonates which are called buffers.  Buffers contain calcium carbonate, borate, and bicarbonate.  Without these buffers or carbonates, corals cannot lay down their calcium skeletons which make up the massive coral reefs found in our oceans.  Corals absorb bicarbonate and process it into carbonate in order to build their calcium carbonate skeletons.  Proper lighting of the correct intensity and spectral range is also required.  Magnesium also plays a role in calcification, without its presence corals cannot absorb the calcium in the levels that are available to them.  Magnesium levels are three times higher than calcium levels in natural seawater and should also be maintained in that ratio in our captive reef systems.  Calcium (Ca) level of 400-450ppm and a magnesium (Mg) level of 1200-1350ppm are recommended for mature corals.  For faster growth of frags and juvenile corals, Orphek recommends a calcium level of 465ppm, Mg at 1390ppm, and dKH at 12.6.  The higher dKH provides additional carbonates to increase growth rate and the higher calcium level compensates for increased calcium absorption by the corals.  Mg is increased to adjust for the recommended three to one ratio of calcium and magnesium.  These increases balance out the water chemistry and they are not raised to a level which would cause precipitation.

dKH (Degree of Carbonate Hardness) is not a thing in the water nor is it an element.  It is a measure of whether adequate carbonates are present in the water to ensure continued coral growth and to keep the pH stable.  Carbonates increase alkalinity levels much more than bicarbonates and well designed buffers should contain about 85% carbonates to maintain a pH of 8.0.  In natural seawater, alkalinity varies between 6.2 to 8.2dKH (depending on location) and is maintained by the occurrence and dissolution of carbonate rocks/coral skeletons and carbon dioxide in the atmosphere.  The presence of carbon dioxide in seawater helps to slowly dissolve carbonates and this is why CO2 is used in calcium reactors.

Now that we have a good idea of how these elements interact with each other in nature, we will move on to how these elements can change and effect other elements and parameters in our home systems.

The ideal pH for our reef systems is 8-8.2.  In the ocean this is easily maintained due to the enormous surface area which exchanges CO2 for oxygen, and the fact that very little dissolved nutrients are present which can acidify the water.  In our captive reef systems this can be challenging, especially if we overstock our systems without proper filtration, air exchange, nutrient export, water flow, and adequate alkalinity to keep pH levels at a desirable level.  Protein skimmers are highly recommended and should be selected at a capacity rated twice the size of your reef aquarium.  This will ensure efficient nutrient export which will minimize buffer dosing.  The two factors which lower pH are excessive nutrients and carbon dioxide and both of these are generated from excessive animal stocking which leads to more animal waste and carbon dioxide.  Fish expel carbon dioxide with every breath they take and this can be minimized by using the largest sump your space will accommodate.  This provides a larger surface area to ensure good gas exchange and oxygen uptake.  A good flow rate in the aquarium is also necessary so water is constantly moving and being drawn into the sump where CO2 can be exported and oxygen imported into the system.  It is not unusual for pH levels to drop by as much as three units (0.3) in the evening because photosynthesis, which utilizes carbon dioxide, does not occur which in turn can lower pH.  Good flow rates also keep detritus and uneaten food in suspension where they can be exported into the sump where scavengers can feast on them and/or the protein skimmer can export them out of the system before developing into dissolved nutrients.  A non laminar flow is highly desirable and the use of programmable pumps such as the Ecotech Vortex MP models easily provides this.  The use of this pump technology ensures good water movement in all areas of the aquarium and is more natural for a coral environment. A total flow rate of at least 12 times the aquarium volume is highly recommended.

The dKH of a reef system should be kept at 7 to 8.5.  Levels above this are not necessary in a well maintained system and are undesirable as it can lead to calcium precipitation.  Acids commonly known to lower dKH levels are CO or carbon dioxide, nitric acids and organic acids, the latter two being derived from sand beds containing large amounts of detritus and from uneaten foods and waste which turn into dissolved nutrients which lead to higher than acceptable nitrate levels.  Some aquarists with heavily stocked aquariums will provide a means of carbon dosing in an attempt to lower nitrate levels.  This process basically involves feeding nutrient eating bacteria with a carbon source which causes them to multiply in large numbers which in turn consume more dissolved nutrients thereby reducing acids in the water.  These nutrient rich bacteria slough off and become suspended in the water column and provide a good food source that are readily consumed by corals and other filter feeding invertebrates.

A word about calcium precipitation is necessary here and we will try to explain this in a clear manner.  Many aquarists tend to keep dKH levels higher than necessary thinking more is better.  This is not the case with buffers (carbonates).  It is only possible to dissolve a given number of solids in a given amount of seawater, and these include calcium, carbonates, and most every element found in seawater.  For a simple analogy we will use poker chips to explain.  If we have a hundred poker chips that completely fill a bowl and seventy of these chips are red to represent calcium, and thirty of these chips are green to represent carbonates or buffers (alkalinity), in theory our bowl is filled and we cannot add any more.  If we rapidly increase the red chips (calcium), some of the green chips (alkalinity) would have to be removed.  So by dosing excess amounts of calcium (red chips), we precipitate the carbonates (green chips) out of solution thereby causing what is known as the “snowstorm” effect.  Many aquarists that see this effect immediately begin to dose other elements in an attempt to balance this out.  This is foolish and will not work, it will only feed the effect by trying to add more chips in an already over filled bowl which can lead to increased precipitation.  This event will have to run its course and only then can you slowly establish a calcium/alkalinity balance within the aquarium.  Calcium carbonate precipitation can be even more drastic at higher pH levels that can occur if Kalkwasser is used and is not slowly dosed.  As the pH rises, the amount of calcium and alkalinity that can be kept in solution without precipitation decreases.  High pH levels will convert much of the bicarbonates present into carbonates which lead to carbonate spikes which again produce the snowstorm effect.  This is why you see residual on the bottom of a Kalkwasser mixing vessel, it cannot go into solution due to an excess of carbonates.

Keeping your water chemistry balanced by regularly testing for pH, calcium, alkalinity, and magnesium will assure continued health for your reef inhabitants.  If you need to raise or lower calcium or alkalinity, do it slowly and do one at a time, not both on the same day.

Orphek hopes this will simplify your understanding of how calcium and alkalinity can react with each other.  Orphek doesn’t just produce high PAR/PUR LED lighting for your corals, we extensively study corals and their reactions to both lighting and water chemistry.  Not only do we produce the best lighting for your corals, we want your corals to grow and thrive and provide this information to you, the aquarist, our highly regarded asset.

Photo acclimation Why and How

Photo acclimation Why and How

by Orphek

When upgrading your lighting to an Orphek high PAR/PUR LED lighting system, a photo-acclimation period may be necessary for your corals depending on your previous lighting technology and/or the light spectrum your previous lighting system emitted.  Most corals are photoadaptive and will adapt to different lighting conditions providing it is within the parameters they require.  Corals that came from intensely lit areas on the reef or aquariums furnished with a similar light source may change their color due to UV reflective pigments they have expelled which causes them to change to a darker color.  The first reaction by aquarists is that the corals are declining in health but this may not necessarily be true.

The change of color may be caused by an increase of zooxanthellae or that more zooxanthellae algae are visible in the absence of the UV reflective pigments.  Corals self adjust these pigments depending on the amount of UV rays that are present.  Whether this change is negative depends on whether the corals light needs are being met by the change in light intensity or spectrum.  May corals can survive in lighting that is less intense than what they are accustomed to in nature.  This also holds true when corals are going from a less intense lighting environment to a more intense lighting environment.  This is called photoadaption.

 

When changing to a different lighting source, some changes that corals may exhibit are often mistaken as improved health signs and this often occurs with LPS corals from the Caryophylliid family.  They may show signs of swelling and exaggerated polyp extension where in fact they are increasing their surface size to gather more light.  This can occur in systems with insufficient light for the corals needs so ensure that you carefully choose the proper lighting system for your corals needs. The best way to measure stony coral growth is by calcification or skeleton growth.  Under proper lighting, corals will usually have a dense rich color and not over exaggerated polyp extension.



There are several ways to photoacclimate your coral; the easiest way is with systems that incorporate dimming technology such as our Nilus Pendant.  With the Nilus you can start with the photoperiod you desire but with 20% intensity.  Each day the intensity can be increased by 5% until you reach your desired output which will generally be 100%.  This final setting will all depend on the types of corals you are keeping.  Most reef aquarists will use full intensity and locate their corals in the system relative to their light requirements.

If using our PR156 which includes two programmable digital timers.  The photoperiod programmed will depend on the depth of your system.  In aquariums that18 inches or less in depth, a 30 minute on and 30 minute off program is a good choice to start with.  Systems deeper than18 inches but not over24 inches can start with 45 minutes on and 15 minutes off.

The timers can then be programmed daily to increase on time by 5 minutes lowering off time by 5 minutes until your desired goal is reached.

Both of the above suggestions are desirable if you are working or away from home for extended periods of time.

Without timers or the capability of dimming, you can photoacclimation by the use of various sizes of inexpensive fiberglass window screen.  Cut the window screen a little larger than your tank size and secure to the tank with appropriate tape or use of aquarium magnets.  Start with a fine screen such as the screen used on storm doors and allow three or four days before changing to the next coarser screen size using the same time period.  After the acclimation is completed with three different screen sizes of increasing coarseness, your corals should be photoacclimation.  Some aquarists may find the above method undesirable or cumbersome, or if all the screen sizes are not available in your area.  If so, you can manually duplicate the PR156 method.
Another method which applies only if you are going to suspend your lighting above the aquarium is that you can raise the pendant to lower the intensity of light entering the aquarium and gradually lower the pendant every two days.

If using the Nilus, PR156, or one of the DIF pendants, the lens or lenses can be removed to lower the PAR value.  Care must be taken here to ensure there is no salt water spray that can get into the LEDs or multichip.

Whether photoacclimation is necessary will all depend on the previous lighting technology used.  Aquarists switching from metal halide to a high PAR / PUR LED system such as Orphek’s, a photoacclimation period may not be necessary.

During the photoacclimation period it is recommended that calcium and dKH levels be monitored as the increase in PAR/PUR levels may cause an increase biological activity.