For those of you who have been following my editorials know that I have been making changes in my system to help enhance calcification by stony corals. Correcting a too high specific gravity and lowering orthophosphates (PO₄₎ levels by controlling feeding and the use of my refugium to grow great amounts of macroalgae has produced the desired effect – PO₄ Levels immeasurable by even a professional Hach test kit (Model PO- 19). These changes have had the desired result; that is, great hermatypic coral growth. See the accompanying picture taken a few days ago. For a very thorough discussion of phosphate in reef aquaria see Randy Holmes-Farley’s column at: http://www.advancedaquarist.com/issues/sept2002/chem.htm.

I also keep a high calcium and alkalinity concentration with the continuous use of a calcium reactor and the evening dosing of saturated limewater to replace water evaporation. My system evaporates about 10-gallons of water daily.

It is quite interesting – some might say annoying -- how the solution to one problem creates or uncovers another. In my case, I noticed that my down draft skimmer was not collecting enough skimmate and, after closer observation, the foam level in the foam column was too low. Not a problem I thought, ‘I’ll just close down on the output gate valve and thereby raise the foam level.’  However, I soon discovered that the large gate valve was frozen.

I immediately recalled Craig Bingman’s discussions (some personal) about some of the potential problems associated with high calcium and alkalinity concentrations – sand bed clumping and frozen pump parts for example. I had to remove the skimmer from the system, remove the gate valve and disassemble my Iwaki 70-RLT and clean all of the parts that were coated with calcium deposits with Muriatic acid (a 20% solution of HCL). Incidentally, Muriatic acid can be purchased in a hardware store. It is, even at 20%, a very strong acid, much stronger than vinegar. It is very important that one use extreme caution when using this acid – it will burn holes in clothing and severely burn human skin.