Hello all! I'am a newbie to the fish world but many of my friends have been doing fresh water for years and some say I need a undergravel system with my penquin biowheel 170 in order to have a dual filteration capacity and others say I only need a power head to get more flow and that undergravel systems will in time hurt my tank with buildup in the plates? My aquarium set up is 34 gal hex, 170biowheel (160gph) maxi-jet 600 power head,and a Jager 150watt heater. I have gone to various fish stores and some say no and some say yes to the undergravel system.... 