Hey! So, I got a new filter, a mini sponge air filter, as the one i had burned out while we were out of town for 4 days. (a neighbor came and took care of Blub). Night before last, somehow the new filter's strength adjusted overnight and lot of brown algae formed. I have white gravel (I don't like it), and the algae did not come off w the gravel vac. With my water change, i took out the plants and used a toothbrush to get the algae off, but this isn't so easy with the gravel. i took a slited metal spoon and took up the top layer of gravel with the brown on it and have it set aside to deal with when i get the time. it won't even all come off when i run water over it and rub the gravel through my hands. The same thing happened with the gravel i had in there before i changed it to the white. that's why i put the white in there. I thought it would be ok to just change the substrates as it's just gravel. Nothing elaborate with soil and sand and such, which i want to do eventually. I love the idea of experimenting with different substrates and plants. I don't want to stress out Blub, either, but I want to do another 100% change soon and put the natural looking gravel back in. I can't stand the white gravel! What say you? What do I do if the brown algae comes back and it won't come off with gravel vac? Thank you so much for your help.