My home made top off

HI,
Well I figured I could jury rig a top off for my salt water system
I plan to use a 5 gal water jug I have several
and use this to drive the air pump.put a air tight cork in the bottle with a air hose and a water line out.


My only concern is to allow a high enough feed to prevent siphon from the bottle once primed with air pressure.
I plan to use a small air pump to pressurize the bottle forcing the water out down a tube to the the sump.
we will see.
I may bury a piece of pvc tubing dril holes in thepvc tubing to allow water to exit into the sump but have the pvc stickin up in the air a couple feet and force the water to the same height as the water bottle this should prevent siphoning when the air pump cuts out and allow a air gap where the tubing enter the pvc.
water physics is such fun..
Doug