I need auto fill tank for RO filter

[geronimo <Jamesw@xxxxxxxxxxxxx>]

   I got an RO filter recently.  Problem is, we have to fill it from a
1 or 5 gal jug manually.  I would sure like to have some info on
building a DIY water storage tank that would turn the RO unit on when
low, and back off when full.  I think it could be done with a 5 or 6
gal plastic water bottle, with a spigot installed in the bottom. I
hear the best type of float switch is actually an air column pressure
switch.  That would have to be rigged to turn a solenoid water valve
on/off.  So if I could find a source for a suitable air column
pressure switch, and an electric solenoid valve to control the inlet
water line, then I would be all set to build it.  Or maybe there is a
tank kit I can buy? Ideas?