I decided to make a change in my QT/hospital tank. I ordered a Penguin 200 hob filter that I will add and remove the two large sponge filters that take up so much room in the 20g. The Penguin will be modded to not use the cartridge but some large sponges instead. It will hold two Aquaclear 70 sponges instead. Basically same effect of my existing sponge filters but not taking up the space in the tank. Will do this in preparation of possible new fish coming.