[Aquattro]

Shane, the clam has improved, but still isn't open as much as before this. I still haven't decided what the problem is, but I'm trying to keep the pH higher to see if there is an improvement. pH 7.8 in the morning is a bit low for my comfort. I'm dripping kalk again to maintain a higher value, so I'll see how that works.
I still suspect that the power heads had some impact, although I feel this is only a slight possibility at this point. The whitening is most pronounced around them, although they are also in the path of the return water. Who knows. I'm making water now for a larger than normal water change, but overall, I'm still guessing.