dKH

[Mikro]

What is dKH and what should it be?

[Entropy]

dKH is a measure of your tanks alkalinity. It is measured in German degrees of hardness (can I say that on a family board? :D ). I think what it should be in your tank depends on what you are keeping. I think a safe number for a reef is around 10 dKH

[bertoni]

http://www.advancedaquarist.com/issues/feb2002/chemistry.htm
http://www.advancedaquarist.com/issues/feb2003/chem.htm
http://reefkeeping.com/issues/2004-05/rhf/index.htm

Those articles might be useful to you.