Please help.

[boyesreef]

i have a 14 bio-cube sitting on my kitchen counter, do not fill it to the point its out of the window, it tells you not to in the owners manual! you fill it about two inches from the top of the window, there is supposed to be a maximum fill line sticker there, and about two inches under that is supposed to be a minimum fill line sticker.

[fat walrus]

I would keep it on the high side.

[V]

its only a false wall anyways isn't it, so as long as you have enough water cascading to cover what every media you got going & isn't creating a return bubble bath your set! If there's indicators, sweet, if not as ampage said, trial & error till it works. Power outage isn't a problem with false wall set-ups so thats not even a factor.