Means of Calcium addition

[stephenlchristopher]

crayola chalk....three twelve packs, at 89 cents apiece, brought my 300 gallon system up to over 400 ppm. The block marking chalk from the hardware store is even cheaper, if you can't swing 89 cents....pure calcium carbonate

[Cuttlefish]

how do you actually dose it though? You use chalk instead of Kalk, 2 part or calcium reactor? How is the tank looking?

[tdwyatt]

Chalk is a form of calcium carbonate, just like aragonite basically is, but chalk is purified and does not contain all the traces, ect., that aragonite does. Remember that aragonite is parrotfish poop, composed of pieces of coral that the parrotfish has passed through its gut to digest out coral polyps. It is the ideal calcium/alkalinity supplement because it is made of coral skeletons. Although IF you can get the chalk to dissolve at a reasonable rate, it will take care of carbonate--->bicarbonate and calcium, you still need something that will make it dissolve at a resonable rate for hermatypic coral in a marine environment, and it will supply nothing but calcium and carbonate, plus whatever the manufacturer might have added to the chalk to make it easier to express as sticks and to not be too friable as a shippable product.