It's better then nothing. I have run one for a couple years on my 46 reef. It works. But, you do have to pay attention to the waste in the cup. You churn to much and she over flows not enough and you arn't doing anything. But, After awhile you will have it tuned to where every couple days you adjust the flow. But, it does work. and if you don't have a sump you don't have much choice. I wouldn't rely on it on anything bigger than my 46 though.