I have my 7in axie in a 20 gallon tank and bought him the same filter I have for my turtle. Its a 501 canister filter (turtle clean) but it will work for axies too. Keeps his water crystal clear. Still have to remove his poo by either siphoning or turkey baster. It comes with a spray bar, so just point that towards the glass instead of directly onto the water and you're all set. It is completely quiet! Only thing I hear is a very slight trickle of water
Another awesome thing about them is that they are not crazy expensive (aaprox. $60 at pet store, but found cheaper online, shop around!), and they are good for up to 30 gallons of water in case you upgrade. They are also durable, I went camping for a full weekend, came home and my turtle had knocked his intake off the side of his tank and it was floating. Filter making HORRIBLE noise because it ran dry, and still works! No clue how long it was out of water, but they are good for up to 30 days dry before damage. So now I have 2, One on my 40g turtle tank (only about 25-30g's of water) and the other in my axie tank showing here.