its about 2 weeks since i set it up. I also went out yesterday and bought a Penguin 100 BIO-Wheel for my hospital tank, which i am going to put my damsel in there till i get my other fish and then put him back in. Anyway, i set up the BIO-Wheel and put it in my 24 gal Aquapod tank just to see how it worked and to get the damsel acclimated to it so when i did put it in my hospital tank it wasn't afraid. So i had my 2 powerheads plus my BIO-Wheel running. This created a good amount of current. I took out the BIO-Wheel today, thats when i noticed the "diatom" on all of my LR. Do you thinks it because of the less current since i took out the BIO-Wheel?