Hmmmm. Well, there really isn't any consensus on what you "need". Most people in the planted tank scene use at least some sort of mechanical filtration. Canister filters are very popular and provide benefits of additional circulation and some biological filtration too. I use two Eheim 2217 classic filters on my 180g tank and thoroughly clean one every three months or so. The quantity of mulm that is "removed" from the system is enormous.
If you have a large enough plant mass and a comparatively small enough fish mass, you can use the plants alone to detoxify ammonia and other organic wastes. People often call this a "veggie filter". Of course, large waterchanges always help too.
If you're fortunate enough to live in an area with the right type of water, you could always rig up a continuous water change system. The only downside to this is the difficulty that arises with trying to keep nutrient and CO2 levels where you want them.
Thank you for your response. I am new to a planted tank, so I am trying to do it right the first time. I have a reef ready tank, so I have to have a sump or a wet dry filter. I could use a wet dry with filter pads or I could have a sump and just put a heater in it and then run canister filters. What do you planted tank people think?
Could I run my reef ready 180 without a sump? I am wondering if I could hook a canister filter to to each overflow. It would be like a closed loop. Would the AGA overflow keep up with a canister filter?
orlando thanks for the reply. I asked this question at a different site and I am being told that a sump will not work on a planted tank. They say CO2 will escape to fast and that I still have to run 2 canister filters. Will a sump work? Anybody have a picture of a sump in use? If I can run a sump with filter socks what other filtration is needed? Thanks so much for all the help I am getting to get this tank running.
i am running a 50gal sump on a 210 all glass with two over flows, you just have to minimize your degassing, i have pulled out all of my power heads and raised both of the over flow tubes to a max as to minimize the water fall effect and the drop checker turned green a day after the power head came out so yes you can run a sump. the video's on my sig are about a year old but will give you a good idea.