[Beverly]

Originally Posted by mooch28

Im wondering why your asking me to reduce my calcium??? Any reason for doing so??

I used to be under the impression that the higher the Ca in my tanks (up to 450 ppm), the better it is for organisims that use it in the calcification process. However, according to this very complex chemistry article, The Chemical and Biochemical Mechanisms of Calcification, more is not better ....

http://www.advancedaquarist.com/issues/apr2002/chem.htm

Here's a quote from near the end of the article. Read the whole article (a few times) to better understand the many biochemical processes at work in calcification....

Implications for Reefkeeping: Calcium Concentration

Reefkeeping hobby lore has it that boosting the calcium concentration above natural levels of 410 ppm does little to enhance calcification in most corals. That idea is supported by experiments on Stylophora pistillata where calcification becomes limited by calcium at levels below natural levels, but is not increased above about 360 ppm.4 The relationship between external calcium concentration and calcification rate displays exactly the behavior to be expected if an active transport process were limiting the calcification rate, and that this transport process is saturated with calcium at concentrations above 360 ppm.

Using some of the information provided in previous sections, we can understand why this may be the case. Again, for Stylophora pistillata, as the calcium level is increased in an artificial seawater medium from 0 to 800 ppm, the calcium uptake by the coelenteron increases in a linear fashion.4 The uptake by most of the tissues other than the calicoblastic epithelium also increases in a linear fashion. There is no data specific to the calicoblastic epithelium, but the data show that calcification does not increase above 360 ppm calcium.

If the calcium is let into the calicoblastic epithelium by a calcium channel, then the influx of calcium is dependent on the concentration in the coelenteron, and the proportion of time that the calcium channels are open. Since the cells themselves control the gating of the calcium channels, they presumably can control their internal calcium levels at will UNLESS there is not enough calcium outside of the cells to go through the gate, cross the calicoblastic epithelium cells, and get to the active transporter that sends it into the ECF. Consequently, one interpretation is that at external calcium concentrations below 360 ppm, the calcium flux into the calicoblastic cells becomes the rate-limiting step in calcification.

HTH