pressure in well leaking down after pump shuts off

I have a 100 ft well, waterace 1hp pump, packer ejector, 2" PVC schudule 40 casing, 86 gal. bladder tank. Been working fine for 8 years. When the valve is closed between the pump and tank with the pump off, I can hear water flowing back into the well and see the pressure drop on the gauge. It only takes about 3 min. to drop from 55lbs to 20 lbs. and then the pump cycles agin. Should I replace the packer ejector or might it be something else?I also started getting lot of sand in water about a year ago but not as bad now as it was. Could the sand have damaged the packer ejector?

I'm guessing this is a jet pump setup in shallow well configuration with a single line down the well. There would be a footvalve at the bottom of the well or a checkvalve at the pump, either of which is no longer holding. People will often just install a checkvalve just before the pump to mitigate a leaky footvalve.

OK, maybe I'm guessing wrong... I cannot find any specs on a Packer Injector but it looks like it turns the casing into one of the two lines needed for deep well jet pumping. I'm sure someone that knows more about these will be along shortly.

I found a manual and it looks like it uses a footvalve.

http://www.waterace.com/pdf/R510 R520 and R100 Jet Pumps Manual.pdf

if it's 2" PVC casing, rusted casing isn't an issue so the problem is likely either the footvalve or the leathers on the jet assembly.

Thanks ! Can I use a Flint & Walling SP20BL 1828 2" packer jet on the 100ft well in place of waterace RP2-3-5 packer jet ? Where can I purchase one ? Thanks agin for the help

Remember to not use a cast iron packer jet in a pvc well especially if your jetline is pvc.

You need to match your ejector with your pump, water level, and pressure needs. You should just be able to replace the leathers and footvalve on your old one and reuse it.

Good luck.