*** done some searching around and cant seem to find a solid answer or others with the situation so i thought i would post up. My 20G has an AC70 on it got it used from a friend. Had it on for about 4 days when i noticed my tank level was down about a gallon or so. So i looked to tank over from top to bottom and couldnt find a leak. But i noticed the puddles were directly under the filter. So i took it apart and found the oring on the motor was cracked and dry rotted. I replaced it and put a small amount of vaseline on it for some lube. Put everything back together and it ran for another two days for me to come home to the same water loss maybe more. I saw the same puddle directly under filter. I looked close at the motor but didnt see it coming out. It almost looked as if the water ran out from the top of the back side on the filter that was the only location i could see any water. Anyone else have this happen?