Calcium and Alkilinity measurements

[75gal.reefowner?]

I read into the advanced aquarist article about trying to balance calcium and alkilinity. I just had one question. It has a chart that shows the ideal amount to have of each for them to be balanced. The calcium is measured in mg\L, which is the same as my test kit. The alkilinity is measured in Meq\L and my test kit shows Dkh, as in 8-12 Dkh. What Dkh level should I be looking for if I have a calcium level of 400? My Kh is at 8 and calcium is at 300 (I'm trying to raise it right now). I am adding calcium to get the level up but I need to know when to stop adding that and when to switch to the two part buffer. Just need a little clarification because the alkilinity measurement is different in that article.

[Randy Holmes-Farley]

I actually do not think that optimal calcium and alkalinty levels (from a coral's perspective, anyway) are necessarily related.

That said, I usually recommend an alkalinity of 2.5-4 meq/L which corresponds to 7-11 dKH.

To convert meq/L into dKH, you multiply by 2.8.

If I were you I'd boost the calcium to about 420 ppm with a pure calcium supplement (like calcium chloride), and then use a balanced calcium and alkalinity additive system going forward. If you want to raise the alallinity, I'd use the the balanced additive system for that.

Here are a couple of articles that might be useful:

How to Select a Calcium and Alkalinity Supplementation Scheme
http://www.advancedaquarist.com/issues/feb2003/chem.htm

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm