Yeah, the issue isn't over filtering which makes about as much sense as your air being "too clean," its the flow. The more you're filtering the more water you're flowing and the more current you're making in the tank.
You're actually a touch on the small side in terms of filters. Given that you've got plants that's not really a bad thing as you don't want a lot of turbulence in the water and the plants themselves can help with the filtering. If I were you I'd stay with what you've got and just keep a good eye on your water parameters.