This looks like a good place to ask questions. I have 2 - 30 gallon & 1 - 10 gallon quaretine tank at home and another 30 gallon at work. I have 4 parrots, 3 angles, 1 huge oscar, 4 silver dollars, 1 borneo bleco, 1 albino pleco, 1 rubber lip pleco and msc. I have had undergravel filters for 20 years and have been researching bio-wheels because I am tired of never getting all the dirt out of my rocks. Besides it makes sense to get dirt out of the tank instead of intentionally trapping it in the rocks inside the tank. Looking forward to discussing fish here.