I have had bad luck a trying to remove a filter after the tank is running. The tank is well established and the filter sponge is well part of the biological filtration. By removing it you will have an ammonia spike creating and algae out break. Yes the plant will start to take up ammonia but this will take time and in the mean while algae will be more then happy to put it to use. The best way to go filter less is to start that way.