Hey, I also got such problem before. I bought many from the shop before. The boss promise me that keeping using that will maintain kh and ph. But when I put in (not so many) all many corals got impaction. Then i go to internet check the brand"reefmax" and found no such brand at all.After study some article about marinefish I think all the ABC...cant be trusted. Now I using redsea brand, a bit expensive than the ABC.. but it is a liquid and when i put in coral all ok . I have using redsea for 6 months, so far so good.