I wish my calcium level was that good. Sort of. I didn't know saltwater could hold that much calcium at saturation level EVEN if your carbonate hardness was alright. If you have a reef tank, I wouldn't sweat over it. Right now, I have to dose my tank almost everyday with a calcium, strontium supplements and a kH buffer in order for me to maintain a proper chemistry. I can barely get my calcium over 380 ppm and my kH drops a little almost everyday. I also blame I/O Reef Crystals for it too. I bought like four 5 gallon buckets and I tested the chemistry of their mix only to realize they were low. I'm NEVER buying Reef Crystals again. Surprisingly, I went back to Seachem Reef Salt and found it to be more stable.