I run HOB's on my freshwater tanks including 2 heavily planted ones. Problems you can run into are leaves and plant matter getting stuck/sucked into the intake, that can be solved with putting a prefilter on, some plants grow better with water current some don't so plant accordingly in relation to your filter output, some HOB's have stronger output too, my Aqueon HOB output makes a current that goes forward across the tank, my Aquaclears as long as the tanks topped off just are more downward with less water disturbance.