What about this one...
http://www.seascrew.com/browse.cfm?PLASTIC-ONE-WAY-VALVES---STRAINERS&l=0000000408
The 1/2" or 3/4" one down the page?
It all depends on what pressure opens the valve though and if it can be submerged in the main tank..
http://www.seascrew.com/browse.cfm?PLASTIC-ONE-WAY-VALVES---STRAINERS&l=0000000408
The 1/2" or 3/4" one down the page?
It all depends on what pressure opens the valve though and if it can be submerged in the main tank..