ok so i got a 60g tank with wet and dry filtration system on the back, ive noticed for a couple of days that my water level in my tank looks lower than usual, ive added water to the back of the tank in the filtration system and the water level keeps lookin lower, its so low it looks like its about to reach my powerhead, what can be causing this? could it be that my pump in the back its goin out???any ideas.....thanks...