I'm using FloraNova only, so Cal may be the prob. Have to pickup some calmag+ this weekend. thanks for the suggestion. Oh, and the water is RO, it's only a 5 gal rez so it's cheap to fill.

Heat shouldn't be a problem, it's actually a little cold most of the time, say in the 60's somewhere. It could spike up from time to time, but not often. Either way, a logging thermometer is the next purchase, so we'll find out.

Thanks for the replies.