Question 1, Calcium

[Beverly]

Originally Posted by StirCrazy

and why do we try to push for higher levels than NSW even though it slows down coral growth?

Steve,

I have never read that higher levels of Ca than NSW slows coral growth. Can you provide a quote and source for this statement? TIA

According to.....

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

Most reef aquarists try to maintain approximately natural levels of calcium in their aquaria (~420 ppm). It does not appear that boosting the calcium concentration above natural levels enhances calcification (i.e., skeletal growth) in most corals. Experiments on Stylophora pistillata, for example, show that low calcium levels limit calcification, but that levels above about 360 ppm do not increase calcification.

Back to your question.....

I do not, and never will, use Ca or other reactors to maintain Ca or other reef chemistry levels. Instead, I drip kalk into our reefs every night to help maintain Ca and alk levels. Then, once every 10-20 days, I test for alk, Ca and Mg, record dates of test results and how much I adjust, and adjust all levels at the same time. Sometimes, if the halimeda in each reef is looking a bit ragged, without testing, I will adjust and record how much I add of Ca, alk and Mg in each reef. I use data recorded from previous test results to ballpark the amount of each chemistry component I adjust without testing.

I know you just asked about Ca, but I don't feel right about just talking about Ca when I do the whole shebang at once. If I were to separate the Ca portion of the three components I test and adjust, I would have to reply that I keep Ca levels between 400 to 450 ppm. I also initially aim for higher alk and Mg levels when I test and adjust the chemistry in our reefs. The higher levels of Ca, alk (10 to 12 dKH), and Mg (1300 to 1350 ppm) are in our reefs so they can be slowly utilized by corals, coralline algae, calciferous macroalgae, etc.

I don't know if what I have just described is a useful way to work with Ca and other chemical components in a reef system. Short of testing and adjusting all components weekly, which probably isn't going to happen, this is the best I believe we are going to have in our reefs.

Hope my comments help the discussion begin