2 eheim 2217s on a 75 gal
Hi! putting in my 2 cents... my completely new as of last summer to tanks of any sort, let alone planted, 2 cents btw... I have a 75 gallon planted with 2 eheim 2217 filters and a power head. Now, I see everyone's point about more filtration not being necessary, but I adopted my tank with all the gear so I never had to spend lots of money! So. Anyways. This is my plug for having 2: did you know you can adjust the flow? you just tweak the little levers on the intake and output valves and you can get the flow just right. I have a lot of wood, a lot of plants, and rainbows who like to have a high flow. In the summer it gets very hot and to help cool the tank I add in the power head too. When I need to clean a filter I can alternate so that one filter is nice and juicy while the other gets a good rinse, and if anything happens to one of the filters I have a back up. Which recently I had to get one repaired and it was at the shop for a couple of days, no stress because I had the back up. I also do a lot of tweaking to get my levels right-- like I have one canister that has a lot of peat in it, the other has a regular ratio of media. The bottom line is that if you can afford it maybe get two, it can't hurt! You could even get to 2213 or something instead.