Is use two part, but only the calcium portion of it. I dose 20ml each morning. My calcium still stays lower than i would like at about 420. But I am having a heckuva time gettin' it above that. I have started dosing my water change water as well to give it a boost (it tests out at 320 from the store). I can dose that a bit heavier and then let it sit for a day with a powerhead running.