Strange Problem With Well System

I have a Well thats about 200 ft deep, it is about 35 years old.
the last few months I have been noticing air in the pipes when I turn the fausets or flush toilets in the morning or evening when the system has been sitting a while and I open the fauset and it spits Air and water for a bout 30 seconds. So I replaced the Check Valves at the Presure Tank and at the Pump in the well. The problem seemed to go away for about a week, now it's progressivly getting worse again. Any Ideas?
There is no dirt in the water, no extra green areas in the yard the pump does not run continuasly. Please help

Not sure what Model the Pump is but the Presure tank is a A.O. Smith AuquaAir V100

Duplicate thread. See over here:

https://terrylove.com/forums/showthread.php?t=14759

leejosepho said:

Duplicate thread. See over here:

https://terrylove.com/forums/showthread.php?t=14759

Click to expand...

That one was removed because it was posted in the wrong section,

Remove the check valve at the tank and you will notice that when the pump shuts off, the water will run back somewhere. It will usually be the droppipe in the well. Then you will probably end up pulling the pump and replacing the pipe.

bob...

What kind of drop pipe is in the well?