[mike31154]

As an interim measure, would your gravity feed work through a mechanical float valve? If you can do gravity, then why bother with electrics at all. I don't have a sump & impractical to raise display top off container above the tank for gravity, so I use an air pump on a timer to pressurize a wine carboy full of water. The air pressure pushes water through a mechanical float valve (Wait brand for furnace humidifiers) into the display. This has worked very well for 4-5 years now.

As far as relays, you might be able to get one at an Auto parts store or Canadian Tire. Many 12 VDC relays for the automotive or marine industry are rated to 120 volts. You do need to check the specs though, they're not all compatible. Voltage & current info is usually on the relay & packaging but you might need to use a 12 volt power supply to run the coil of the relay. Chances are you'll have a few of those around the house. Speaking of which, if you have any old, defunct appliances kicking around, chances are there's a relay or two in one of them you can scavenge.