I have an externalcanister filter with uv and an internal filter just for the extra flow.
Yeah and regarding tank size I too know it's small. Will be upgrading in a few months. Right now aro is 10 inch and ray is 6 so they are just managing but I know it is not an excuse to keep them in this small tank for too long.
Thats not enough filtration for that tanksize and stock. You should prob do 50% twice a week in your tank with that bioload.