I'm only giving 3 stars. While it does what I need it to do, mostly, I would very much like to add an airstone inside as the bubbling is way too vigorous and I can't see how to do that. I'm primarily using it on a battery powered pump for emergency, in a 6 gallon Fluval Edge. So it's only on occasionally when I run it for a half hour to test the system. I would run it more with airstone-like bubbling but this is too intrusive as is.
This is a semi-circle at a right angle but it works out in a square tank. Works as described!
These came earlier then tracking said. Was super happy my betta love them use them for bed.. keeps water clean love them
Haven't actually used them yet, but they did come in good condition. They will work great for the application I have in mind, just no time to set up the tanks atm.
Will fit perfectly in the corner of a smaller tank... Or wherever you want to put it! Not as easy to amend for use with an air stone, but it is doable if you're determined!