It seems every time I go to refill either of my iClear 30's, they gurgle and leak.  I don't wait until the fluid gets all the way to the bottom, though.  Might that be causing it?  I know I'm not overfilling them, as I don't even fill them to the top.  I love my iClear 16's, but the iClear 30's are giving me headaches!  