I had the AC30 on my 29 gallon tank, and it kept that one clear. I dont remember, is this one planted, or no? If it is planted, you may need extra filtration, but that is not my area as I dont have a planted tank. I know my bottom dwellers kick up a lot of debris into the water, and my 2 filters before the RenaXP2 was added, the water got a bit dirty towards the end. This could be due in part to the mini cycle at the moment, but I felt better to add a third filter to keep the trash to a min anyway. The AC3 is a good filter, and moves water efficiently with little disturbance to the fish, the AC50 moves a good amount of water but has a rather strong return current. The AC50 was moving stuff on the bottom of my 29 gallon tank at full strength. The filter floss will catch the particles your sponge wont, but will also clog easier and faster, as you likely know running it in the rena.