pacu mom;2723463; said:You have enough biological filtration if your ammonia and nitrite readings are 0. Adding more filtration will not lower your nitrates. However, something like an FX-5 will give you more mechanical filtration (depending on the media you use). You know what they say---you can't have enough mechanical filtration. You can always justify an FX-5 for redundant/back up filtration. That's what I use mine for. It came in handy when I added a UV sterilizer to it to clear up a green water problem in our tank. It definitely gives peace of mind knowing you have backup filtration should you ever need it. It could also be used to quickly set up a hospital tank.
Lets hope its a big hospital tank
