When to start adding kalk?
 

Hey everybody,

I have a 20 gallon long tank with a couple fish a dozen snails/hermits, a birdsnest, a monti, a frogspawn, a hammer, a candy cane, a dincan, and a couple other unknown stony corals. So far my IO 18% weekly water changes keep my kh at 8.5-9, calcium at 400-420ppm, and Mg at 1290ppm. I plan on adding a bubble coral and a clam.

My question is, how do I know when I should start putting kalk in my ato water?

Thanks!

At some point, the alkalinity might start dropping quickly enough that the water changes won't keep up or become a bit expensive. Until then, I wouldn't worry about it.