"I read so many positive reviews about this product that I had to get it. Bad decision. I have a fine sand substrate and it sucked up the sand, tons of water, but left the fish poo, etc.
Also, if your fish are curious like mine, you better make sure you concoct some mesh over the end of the tube or you're liable to easily suck one of your fish into it.
I would say if you have a 100+ gallon tank, this would be good. For my 56 gallon with fine sand substrate it is the wrong fit. I am bringing it back tomorrow.
Now, when I look at my tank, I see large holes where the sand was sucked up and all the fish poo that I thought it was getting is filling them in. Oh well."