[niko]

It's just and idea, and I was wondering if someone had tried it:

Get some crushed coral (or another Calcium containing material) and put it in a container with water. Bubble CO2 in the water so the coral disolves and the water ends up rich in Calcium.

--Nikolay

 

[gnatster]

A Calcium reactor, common in reef tanks as corals build their skeletons from Ca. These are designed to keep Ca in the range of 400 ppm. Has the effect of keeping pH high, around 8.4 and water very hard, kH 12-14 GH 16-18. Great for reef's where you dose Ca every day.