I have a 3 stage sump on my 125 gal. Its about 25 gal, 1st stage is filter floss which I clean or change with every water change, 2nd stage is bioballs, 3 stage is return with a 900gph pump. I am a believer in increased contact time with the media to promote efficient biological filtration Soni don't use a crazy big return pump. It's super easy to maintenance. I have a 1/2 HP pump I use to vacuum the return section of fine detritus that makes it through the previous stages, I do this monthly. I also vacuum my tank diligently every 2 weeks. I love the sump for ease of cleaning.