MBZ,

I would rig up a small pump that come on before the main one and gives the pump it's prime before starting up. That would take care of trying to find small leaks in the pump, BFP and lines. Aloha

Ok first how certain are you that your well is 10'. I see your name tag is Miami so I will go with your from south fla like I am. By law wells in south fla have to be 20'+. At 10' here in south fla it is possible to draw under. What this means is your well has water but your drawing so much water that you draw air. If your well was 15'+ deep this couldnt happen. What is the well made from. At that depth it is possible your well is plastic rather than from gal. pipe.

Take a 5gal bucket and discharge water from the pump into the bucket while the sprinklers are running if possible. If you cant do both at the same time just discharge as much water as possible into the bucket for 2-3 min. Let the water be very still for 10+ min. Carefully pour off the water so you dont stir up the bottom. If you find ANY sand in the bottom your well is bad. I would hazard your getting small amounts of sand and when a piece sticks in your check valve you lose your prime over a long period of time. Also check valves can go bad. If you have a dischage gate valve (or ball valve) shut off the discharge and fill up the pumps dischage pipe very carefully making sure there are no air bubbles. When the pipe is 100% full see if the water drops at all. If your check valve is perfect there will be no drop.

One other possible issue with your pump is the pump seal and/or the pump stainless strap. I am going to guess you have the plastic headed FloTech pump. This stainless strap if not tight enough can slowly allow water to leak out of the O-ring in the head of the pump.

Good luck,
Tom