I have quite the dilemma, i set up my 90G again for a new stocklist, and its an open top tank, i filled it up, and overnight 1/4 of the water was gone, i thought i was evaporation, so i refilled it and put a piece of glass on top, i come home from school, and about 1/5 is gone, but no water on the glass... so no evaporation... i was thinking it might be the driftwood i have, it was dried out, could it be absorbing the water as it becomes water logged? 
