I have a 90g with a 45 refugium and I am trying to get my calcium to 400 and my DKH to 12. I have over the last week, added a lot or both, checking the next day on Salifert tests and i still seem to be stuck at 300 calc and at the highest 8 DKH. All my corals seem to be doing fine excet a leather that will not open up now. I am stopping anything until I get better educated at this. I have read several of Tom's posts, and it seems like I am on the right track, just not seeing th efruits of my labor here. I use RO/DI water. I use B-ionic calcium buffer system #1 and #2.