I have been having my alk drop slowly overtime. The first time that it got low I brought it back up with baking soda very slowly. When it happened again over the course of a few months I thought the magnesium was to blame so I ordered a Mg test kit. Well Mg levels are spot on and so are Ca. I dose seachem 2 part for Ca and KH. I do notice quite a bit of precipitation when I add the KH though. Maybe this is why it keeps getting low, because it precipitates out instead of going into the water. Any ideas why I am having this trouble maintaining good KH. Today it was all the way down at 5.6 dKh (2.0) when I tested. I am currently dripping somebaking soda overnight but I need to solve the cause of my problem. Corals aren't growing very fast with the unstable and low alk.