I lost two cleaner shrimp that seemed fine. After the fact I discovered my calcium was at 300. I've got two buckets of Instant Ocean mixing at 350 and I guess monthly 15% water changes weren't able to even keep it at 350. Anyway, was CA at 300 a likely cause of the shrimp kicking the bucket? I had them for about three months and they were medium size. Died about two weeks apart. Molted several times for about a month and a half, but I don't remember any molt the last month. Periodically dose iodine.