PRO CLEAR 75 WET/DRY FILTER HAS BEEN WORKING OUT GREAT FOR MY TANK AND INHABITANTS FOR OVER A YEAR KNOW. VERY LOW MAINTANENCE. PRE FILTER MIGHT GET DIRTY ONCE A MONTH BUT I DONT HAVE A HIGHLY POPULATED TANK. HAVE NEVER HAD TO CLEAN BIO BALLS BUT I KEEP PRE FILTERS CLEAN. MY WATER PERAMITERS STAY AT IDEAL LEVELS WITH 10-15% WATER CHANGE EVERY TWO OR THREE WEEKS. I KNOW YOU SUPPOSED TO CHANGE EVERY WEEK BUT NUTRIENTS SEEM TO STAY AT IDEAL LEVELS SO I DONT SEE THE NEED. ALL IS THRIVING!
