[reefburnaby]

Hi,

Kalk dosing is a bit tricky if you haven't done it before. The entire concept lies in having CO2 in your tank so that it can react with your kalk (CaOH2) mixture. If you dose too fast, there isn't enough CO2 in the water to react...so it actually precipitates in your tank. CO2 is generated by your corals and fish. If you dose too slow...well you might not add as much calcium as you want. The rate that you dose is also dependent on how much evaporation you have -- no evaporation...tricky kalk dosing !

So, how fast and how much you dose depends on your tanks demands and it should be adjusted accordingly with an appropriate test kit. Usually, the tank generates more CO2 at night since corals consume O2 at night -- so it is better to dose at night. Most reefers just add kalk in to their top-off water and dose continuously.

The other problems with kalk is reaction with CO2 from other sources -- such as the air. This is why we try to keep the kalk away from air or keep the kalk mixture fresh (i.e. new batch every day ...up to three days). Once the kalk reacts with the air, the Ca++ ions in the mixture become CaCO3 (calcium carbonate...solid) and it is no longer useful to the corals.

The other thing to watch out is that kalk can not raise alk...it just maintains it at best. So, buffers will need to be supplemented from time to time to maintain decent levels.

Hope that helps.

- Victor.

[ 26 September 2002, 23:30: Message edited by: reefburnaby ]