Slurry method using a small pipet, a measured amount of calcium hydroxide (based on results of calcium test kit compared with tests from previous days), and just enough
RO/DI water to turn the calcium into a paste. This is done in the main display about an hour after lights out, up to three times a week if needed. Never added more than ~3g at a time or ~10g in a week, and usually I add much less, since there aren't many fast-growing calcium-using corals in my tank.
I should go back to using a slow drip running all night with my top-off water, though. I've acquired a VERY bad habit of adding the
kalk slurry WITHOUT having an accurate electronic
pH meter in my other hand - a potentially dangerous habit even with the modest amounts of calcium my tank uses.
