Leak at well/water tank

I just found a small leak coming from a pvc connection going towards our well tank. See the picture.

I'm capable of doing light plumbing but this one has me worried because I dont know how to shut off pressure from both sides of the leak.

The leak is between the well tank and manifold to the tank. I assume there is pressure on both sides (pressure from the tank and siphon-like pressure from the well). I think the gray device to the left of the leak is a check valve so that would help.

Any thoughts?

Thanks
Joe

You shut of the water to the house with the red handled CPVC ball valve.

You shut off the power to the well pump at the panel box.

You drain the water out of the well pressure tank through the black handled boiler drain valve and a garden hose, or piece of hose.

The gray thing... I've never seen a check valve like that before. It makes me think it might be a backflow prevention device but... either way, I suggest you remove it when you fix the leak. A check valve there prevented you from knowing of problems in the well; like a leaking drop pipe or pump check valve.

No - don't remove the backflow preventer. It's there for a reason.

I've worked on a fair number of wells in 20 years and speak to as many as 2-3 people with wells 5-6 days a week. If that is a backflow prevention device, it's the first on a well that I've ever seen or heard of.

What is the reason for it?