Honestly, you get what you pay for here, and you’re not paying all that much so don’t expect it to be the greatest thing ever.I have a 55gal terrarium so I need an in-tank filter unit. I got this one at a petsmart a while back since it was a good size and I probably only have about 20gal of water. it did it’s job for two years, then broke (they really were on point with that warranty). while it was working, though, it worked well. it kept the water clean and the substrate was aerated enough to keep the ammonia down. I have an algae eater and a few large snails and between them all they do quite nicely at keeping the tank clean. my only small issue outside of it breaking almost immediately after the warranty was expired is that the suction cups weren’t quite strong enough to keep the unit elevated and upright, although my painted turtle would lean on it occasionally and that probably doesn’t help.I’m getting another one since it worked well enough, it’s cheap, and I still have replacement filters for it.