[pogodzib]

Clams can really suck up a lot of Calcium.

Depending on what you do for topoff water, kalk can be the easiest thing to dose. It is a balanced solution, so it adds to your calcium and alk levels equally so you don't need to worry about getting your parameters out of balance. If you have a automatic topoff device or float valve and a bucket, you can just fill the bucket with kalk water and it would gradually get added into your tank all day long, so you wouldn't need to do the whole drip thing. All you'd have to do is figure out how strong of a kalk mixture you need to keep your levels stable. If you start getting too many hard corals, then kalk alone isn't enough to keep up. Using two part solutions is good for getting your levels back into range.