ok substrate test inprogress.

[One_Divided]

I've got a bunch of silica but havn't tested it yet.. Very nice and white. steve, you are welcome to experiment with some if you want..

the feedback I've gotten on it is that it may lead to silicates breaking down in the water and therefor more algea growth, but I'm not too sure about that.. some say it's fine but doesn't offer the buffering or anything.. just denitrification..