I'm trying to build a gravity auto top off for my display. I took a reef crystals bucket and drilled a hole in the bottom of it. I have a tube coming out of the bottom connected to a ball valve. Then that line will go to the tank to fill it up. The bucket is sealed air tight with screw on lid. I have a hole drilled in the top of the lid and I used a bung, for a wine carboy, with another air line. This line will also go to the display and will allow air into the bucket, to push water out, when the water drops below this line. My question is, what level would be the best for this bucket? Level with the tank, lower, or higher? I know it can't be too much lower for it to work that way. I just want to make sure I have this thing setup right. I have been testing it in the kitchen and it works pretty good. Any other help is welcome.
