Quote Originally Posted by Puffzter
Sounds like a possible pH problem to me.
Do you have that under control?

Puffzter
My pH meter is kind of crappy, (one of these) I should have bought digital and I might do. The pointer stays right in the middle of 7. I suppose that makes it a max of 7.5. The run-off water is slightly lower, about 7.2 I'd say.

If this is enough of a problem I can buy some phosphoric acid and lower it a bit. I didn't know it would be so picky.