I have a 46 gallon bowfront aquarium which I started off using a fluval 205 canister filter. My water was very poor quality, turned brown after about three or four days, then I was advised not to use tap water so I purchased a reverse osmosis filter and did a complete water change. Throughout the process, I added live rock as afforded. I was still having a problem with water turning green and then brown so I was advised to purchace a protien skimmer which seemed to reduce the water coloration problem greatly but not completely. At this point I have about 45 lbs of live rock, no corals and a few fish such as tangs, clown, damsels. I wanted a better system for filtration so I purchased a sump filter with built in protien skimmer and bio balls. Water seems to stay clean for months as long as the filter maintained. I still have algae growing on the walls and live rock. I am having an issue with the noise level of the sump filter and was thinking about going back to a canister filter that is a wet dry eheim model and using it exclusivly. I would love any advise I could get. Thanks, Bill.