Some people do that and there's no harm in it, and you got the right idea, just make sure to have a way to control the water flow
I personally have the Marineland Penguin 100b bio-wheel. It's rated for up to 20 gallons and I'm using it for my 10 gal.
The water flow is pretty strong so just find a way to baffle it. I've tried the plastic bottle method and it work wonders,
but I've switched to using a sponge to baffle it and its perfect! Also I'm hoping that it'll become another place for beneficial bacteria to grow on
Hoped that help you somewhat