I got the tubing to go on a little more, but not 2" like they suggest, more like 1 1/2" and I clamped it. I can't even take it off.
And I just ordered the damn thing. I should've gotten a newer model.
Anyway, the vet just returned my call. He said he has no idea what the hell it could be. I told him that I had samples, so he said to drop them off so that they can have the lab test it. That'll have to wait, though. The expenses from Harvey's vet visits and her new set up have me penny pinching at the moment. And I still have to make the above tank basking area. (sigh)
Harvey's a girl, by the way.
Thanks for the tips and your input, everybody!