I would keep it on there. Great for running AC and some mechanical filtration. Especially if you don't have a sump or fuge.
Do you have any other type of mechanical filtration, like a canister filter, sponges on power head intakes or such? and do you have anything that skims the surface of the water?
Some type of mechanical filtration is helpful in most all tanks but you want to make sure you clean the media frequently to prevent nitrate production. Surface skimming is also important IMO for good oxygen exchange. An easy way to skim the surface using a hang on filter is to build an overflow box into the tank and put the intake of the hang on filter inside the box while the return dumps into the tank. You can also make your own simple filter that will do the same thing using a power head. Here is what I did in a 10 gallon tank. The filter sponge does the mechanical filtration and the overflow skims the surface without having to drill the tank. Just cut a piece of sponge to fit the size of the overflow box.
It is important when using this type of filter to keep your water level up so the pump doesn't run dry.