The subject pretty much says it all. I've noticed broken shells in my
Flourite, which I didn't put in there, could that be the culprit? I
can see that raising it a bit, but by 6 degrees? Is Flourite even
supposed to have shells in it? In case it matters that much I have 2
inches of Flourite in a 20 gallon tank. Any help you can give would
be much appreciated.

Ken