Auto Water filler

I read one webpage about a tank that had a smaller sealed tank above it and a small tube from the botton the to the desired water level, and once the water would evaporate enough to let air in the tubeand chamber / the camber would naturally start flowing water into the main tank... Are there any of these avalable commercially and or plans to make these...

It basicly works on the same pricable as those automatic water bowls for dogs and cats with the two liter bottle attached to it... I fust don't want a two liter bottle stcking out of the top of my tank to accomplish this automatic water system.

I was thinking i could make one from plexiglass but I have never done plexi work... seemspretty simple however..

Well that one kind of looked like a 2 liter bottle sticking out on the tank.. not reaaly attractive... your right it has to be low profile..

If a guy could find some 3 to 4 inch clear acrylic tubing, like a PVC drain line but clear you could make one that sat the length of the tank and hung on the back ... It would be really easy to construct, you could do it with PVC but then you could not see how much water was left in the "top off unit"... It would provide at least a couple of gallons of water "automagicly"

Very simple, a tube of water with a small tube sitting in the tank where you want you water level at, As long as the water chamber is sealed it will work.

Any one know where to get big clear plactic tubes? and end caps for that matter...

Interesting, expensive stuff, Maybe making a plexi glass box would be more cost effective... Ill have to look at my setup once im get all my stuff setup and figure out a design.