How high do you keep your water level in the tank?

i go as high as i can, like others, dont like the water line.
 
i go all the way to the top, that way i have a week between waterchanges.

one of my tanks is sort of off a bit and that one i fill it til the water is at the edge of the low corner. usually this allows the air bubbles to clean the algae off the glass. :D

1 do have 1 or 2 cheaper 10g's that will leak if you do this, but all my all-glass tanks are fine with it.
 
I fill it up until I hear no more sounds from falling water from my HOB's

The betta tank stays lower so that he has a warm cushion of air to breath from because the room he is in is a little on the cool side.
 
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