I've been trying to raise my alk and calcium and get them balanced, and have been testing on a regular basis. I tested my water for calcium using salifert three times and got a reading of 385 and 390. I took a sample to my lfs store and they tested it with a salifert kit and came out with 490 so way out. The question is who's do i trust and what can I do to find the right result ? My kit is about 2 years old, but hasn't been used allot so I don't really want to get a new kit, do I need one ?