My (salt water) aquarium has 200 litres (around 45 Gal
) and I have a biological filter open to the water and a mechanical one connected to the bottom board.
The shop owner that sold it to me and helped me assemble it says that he has good results with the bottom filtration and that it keeps the aquarium cleaner.
The thing is that two other shop owners told me that bottom filtration is not good because a lot of the waste stays in the sand (I have thick coral sand) and gets decomposed there, polluting the aquarium.
Does anyone use bottom filtration?
I'd like to hear some more opinions on this.