I have a 30 gallon with a canister filter but I was getting a lot of dust and film on the surface, nothing removed it. I got some info from Fishlore about moving the water so I decided to get a circulating pump. This one was mid priced and was a great purchase. Film cleared up in about an hour and water is super clear. With the film, the light had a difficult time getting through the film, so this pump really solved my issues and its super quiet

I've got 2 of these on my 65Gal tank and they seem to work really well. The only issue they can get a little loud at times and they've been in my tank for under a year and seems like one of these pumps are slowly dying. Not 100% sure yet it got extremely loud and had to unplug it for a few days and right now its been running for the night and haven't heard the pump scream yet.

Pretty impressed with this. Lots of water movement for such a small impeller. Easy to adjust position and use, I just wish it had some way to control the speed.

I did manage to crack through a 10 gallon with the magnets. Be very careful when repositioning. It was totally my fault so no stars lost. I lifted up on the magnet on the outside of the tank, and it slipped from my fingers and snapped back against the glass, causing it to crack. The tank still worked fine, and would have been easy enough to replace just the broken pane, but I didn't want to risk it and I just replaced the whole thing. I suspect the thickness of the glass played a huge role the crack occurring, but I also expect other people are using these in small tanks with thin glass as well, so watch out if this is the case for you too.

I would totally recommend this to any aquarists, but I would caution them from moving the Hydor Koralia once it is installed, as you risk issues with the magnet as I had. Total user error though, so also totally avoidable and shouldn't cause any concern to potential buyers.

Good flow, but the way it connects to the magnetic base doesn't give it much room for adjusting the direction. Also the cord is stiff and bulky, making it difficult to cleanly route the cable, and gives another restriction when trying to aim it. Using it to mix up 3-4 gallon batches of water.

Perfect for my 5 gallon saltwater nano tank. Moves the water around nicely, but not too much. I recommend it!