Ok, I want to add a HOB filter to my tank to increase turnover rate. The turnover rate now is about 6 in my tank. My tank is overcrowded so until I upgrade I need to increase turnover rate. I will add one HOB filter but I don't know how many gph yet. The problem is that my tank has a plastic hood which sits on the tank and all the edges can't hang a filter. So what should I do? I prefer HOB filters...