multiple check valves with bladerless tank

I read the sticky on this, looks like an additional check valve is recommened (other than one in well)when using air over water bladerless pressure tanks, why is this?? And also if I nned one please let me know if this is the correct place in-line for it: here is my set-up...from well I have a spin-out sediment filter, then air injector, then pressure tank, I was planning on putting it between the filter and air injector.


Also, I have a relief valve at well head, tank is under house, do I nned an additional relief valve between check valve and pressure switch?


Also..,.. when I hook up water for first time, do I just let tank fill up and it will do the rest? No need to add air?? tank has air control vallve with a schraeder valve and pressure gauge. Pressure switch at 30 and 50.

The air injector should put air in the bladderless tank. So you don't need a bleeder orifice or check valve above ground. You wouldn't want to squirt air through the sediment filter anyway, so this would need to move if you have a bleeder orifice. With the tank empty of water, it will have about the right amount of air when you turn on the pump. No need to add air to the tank, your injector should do that for you.

By air injector do you mean a micronizer? Bladderless tanks are used with micronizers or with snifter/bleeder as they have an air volume control to vent off the excess. Only the snifter/bleeder needs a checkvalve after the snifter but before the tank.