I installed my tank and pump as shown in the pic above. Someone told me that I had to move my pump because it is gravity feed and has to be lower than the tank. Is this true??

 

bump

 

nope,

The pump pressurizes all your lines so gravity shouldn't have to do anything with it.
A water tower in a town uses gravity, maybe that person is thinking about that concept. The pump will also suck what's in the tank. If you're worried about air getting into it, I'd check for air leaks. But if you had a lot of air leaks you'd have liquid coming from somewhere.

 

I have heard the same thing and am considering a similar install. I was just going to be safe and mount the pump a little lower than the bottom of the tank. I have been told that these are pusher pumps not puller and will not create enough vacuum to pull fluid from the tank if they are mounted "well above" the top of the tank. I think your would be fine since the fittings on the pump are so close to the bottom of the tank. You are going to run a low level indicator right? Just set it so it's higher than the pump fittings.

Josh