Just wondering if anyone has tried it, I have not even tried a pressure tank pump yet all thought its on my to do list. My understanding of a pressure tank pump "may have another name for it" Is you have a sealed tank say a 55 gal drum 1 inlet 1 outlet inlet pipe is submerged in water say your fish tank, very first time u use it you also need an air vent on the top say a ball valve so first time u use it you hook a pump up to the inlet pipe and open the air vent also need a ball valve on the outlet so close the ball valve on the outlet. Now fill the tank oh ya I am forgetting a 1 way valve on the inlet to only let water in not out.

So now you pump the tank full of water once water starts coming out of the air vent you can stop pumping, remove the pump now watch to make sure your water level does not drop "this is to check the 1 way valve which should be near the start of your inlet pipe near where you had the pump I believe. So now you have a tank full of water with no air in it a 1 way valve on the inlet not letting the water escape and a ball valve on the outlet also not letting the water escape so now you have your outlet pipe going into your grow bed "above the max water level I believe" open the valve grow bed begins to fill once it gets to top of your Bell Siphon it drains into your fist tank, which also happens to be where you inlet for you pressure tank is.

Now remember there was no air in the pressure tank so whats going to happen as water exits that tank? It should create suctions which will refill the tank at the same time or close to the same time that it is emptying. Thus you no longer need an electric pump.

If I am way off let me know but I believe the theory is sound as long as I did not screw up part of it I am sure if you do a search online you can find diagrams etc of how it works, I just have never tested any of it again on my to do list, just wondering if anyone has tried it.