Saltcorner
By Bob Goemans
By Bob Goemans
Hello Bob,
Hope all is well with you and yours. I am having a difficult time raising the calcium level in my 20 gallon reef and I read your suggestions on line and your Water Quality book on calcium reactors. But at this time it's a little difficult to justify the purchase of a reactor for a small "test" tank. Therefore, if you can, could you recommend a 2 part buffer/calcium supplement? I would appreciate it.
Currently I am using separate calcium and magnesium additives per my LFS. When I added the calcium the pH fell to 8.0 from 8.2. Then I was told to add the magnesium to bring up the pH. The magnesium level was 1140 ppm before I added any magnesium supplement and at that time my calcium level was 350 ppm and alkalinity was at 9.6 and the pH 8.0. After adding magnesium for 3 nights my readings were as follows; salinity 1.027, pH 7.8, alkalinity 8.6, calcium 350 ppm, and magnesium 1190 ppm. The tank also has a 10 gallon sump with a Prizm protein skimmer, a Magnum 350 canister filter, and Eclipse Bio Wheel with charcoal pad filter. I also have two Rio pumps in the sump and the lighting is two 15watt actinic bulbs from Coralife in the canopy. There is one damsel, 2 cleaner shrimp, a few snails and crabs from Garf's "janitor crew," and corals are 2 Ricordea, 1 small cluster of zoanthids, and 1 larger cluster of zoanthids and some green mushrooms. The substrate is 2 inches of live sand, 2mm - 5mm of CaribSea special reef sand.
Thank you for your time and patience.
Sergio Aguilar
Seaford, Long Island NY
Hi Sergio,
A fellow New Yorker, and thanks for your letter. As for a two-part calcium/buffer additive, I'm presently using ESV and/or Warner Marine brands in my nano tanks. Both of these brands, along with quite a few others are excellent for properly maintaining calcium and alkalinity levels, especially in small tanks. And besides, they are more cost effective than reactors. And yes, water quality can be an issue in these smaller tanks.
First of all, there's absolutely nothing wrong with a pH in the range of 8.0 - 8.2, so getting advice to add magnesium to raise it is quite poor!
As for the use of magnesium, its need should be related to the systems specific gravity, not its pH. But if you see a major 'difference' in pH levels between early morning and mid-lighting timeframes, then possibly there is a need to test and correct the magnesium level. A good yardstick here for reef aquariums is, if you do not have access to a chart depicting its relationship to salinity/specific gravity, is about three to one, i.e., 1200 ppm magnesium to 400 ppm calcium.
Since I don't see a problem with bioload or equipment, would suggest a major water change, and upping your calcium level. Probably the quickest and safest way to raise calcium is with Calcium Chloride granules, however, only occasional use of this product is recommended, so as not to skew the chloride level in the aquarium. I suggest using the ESV brand as they have precise info on the label on how to do it. Occasional use of this product will put your calcium level back on track. This and the balanced two part calcium/buffer additive should then keep you on track. And a good target to shoot for at 9.6 dKH should be about 425 ppm. Also, you might want to use CaribSea Purple-Up, which will help balance out calcium and alkalinity readings in your aquarium, besides encouraging coralline algae.
And one more trick, when you do water changes, probably a few gallons at a time, add one spoon of Tropic Marin Bio-Calcium to the pail and give it a day to dissolve. Simply drop a small powerhead in the pail and let it run for a day before using the new seawater.
Hope this helps,
Bob
