Hey guys, just wanting some opinions on my filtration. I want to do this as cheap as I can, but I don't want to skimp. So, I currently have a 120 (60x18xforget the exact height) with a couple 5-7" jacks, 1 8" carpintes and 3 syno cats. This is being filtered by 2 rena xp4's and the water is crystal clear and they do a great job on filtration! Last night I got a 135 (72x18x24) Oceanic tank from a buddy of mine. The current stock is in my 75g filtered by an AC110. Stock will include 1 oscar, 2 Gt's and not sure what bottom dwellers yet. My first option I am thinking is to have 1 xp4 on each tank as bio filtration and use the AC110 I have (purchase another AC110) and run AC110 and xp4 on each tank. Second one I was thinking is just using 2 AC110's on the 135g and leave the 120 alone since its working great. What do you guys think?