Sandpoint problems: too shallow?

I am trying to properly plumb a sandpoint well. So far, I've gone down 17' and found water, so I went down to 20.5' to be extra sure. I have 1.25 galv. pipe with a 3/4 hp pump and a 14 gal. tank. My problem: the pump brings water up the pipe at only 2 gallons per minute, AND I have air bubbles in the line. So, I put a 3/4 pex pipe down the galv. pipe and connected it to the pump. Now, the water comes up OK, but soon after, the water does not flow at all. I actually hear a gurgling sound down the pipe (like the sound of a straw sucking water in a near empty soda glass). Next, I tried lowering the galv. pipe another 2 feet down to 22.5. But the symptoms are the same.
I wonder if this galv pipe needs to be deeper still, or perhaps I could connect a second sandpoint in another location to the same pump. I have an area that is perhaps about 80-90 feet away from the pump, but is at a slough of water, that seems to be wet almost all summer. Perhaps a good spot to send more water over to the pump? However, I'm not sure the pump could pull the water that far away from the first well, if they were hooked togehter. I have more ideas, but this would be getting too long.
So, any help/ideas would be appreciated, as I've never tried this before.

surface water is unreliable by nature. going a few feet under where the water starts won't let you run it for long before you start sucking air. plus you have to consider the depth of the top of your screen, once you drawdown below that you pull air. so go deeper and hope that you're still in material that the water can flow through.

17' is a long way to draw water up with a jet pump, 20' is about max. Starts sounding like pumping gravel when the water is too deep to draw up. You are probably going to need a two pipe, deep well jet pump, or a submersible.

I am not sure what to do now, but I think I'll try to drive down the galv. pipe another couple of feet in hopes that the water is available there. My pump pumps water strongly for a short period of time, but then seems to run out of water. I believe that the water is there, but maybe a little lower. I know I can't go much deeper and still lift that much.

That is what I mean. The pump will run when the water level is high, but running the pump makes the water level low, and the pump quits pumping.

I am not sure what to do now, but I think I'll try to drive down the galv. pipe another couple of feet in hopes that the water is available there. My pump pumps water strongly for a short period of time, but then seems to run out of water. I believe that the water is there, but maybe a little lower. I know I can't go much deeper and still lift that much.

Unless you hit a pocket that makes the water level come up, going deeper probably won't help anything. You will need a two pipe jet pump, and with that size casing a packer as well.

I wouldn't give up yet, I really think you had rigged it for failure at the start and now you're blaming the wrong thing and potentially costing yourself a fortune.
how long is your well point? 3 feet? 5 feet? even if it's only 3 feet the fact that your water level is around 17 feet and you only went down 20.5 feet only give you 1.5 feet of play with the water level before you're sucking air. i'd want at least 6 feet of drawdown play in a shallow well so if your well point is 3 feet long you need a depth of 17 + 6 + 3 = 25, more if the well point is longer.
at any rate you'r getting close to drawing from depths where it gets much harder but not impossible for your pump. but there's a solution if you are willing to put in the man-hours. dig a big pit next to your well and build a simple underground housing for your pump. make sure you're gaining the advantage of the fact that you are lowering the elevation of your pump and thus decreasing the distance it has to pump up water by having the pipe elbow directly into the pump/checkvalve IE do not have any pipe that the water has to travel through to get to the pump that is at a higher level than the pump itself.

people bang 1.25" galv down PLENTY deep. you're not approaching any depth limits there as long as you're using a properly heavy tool to hit it with. sledge hammers are not ideal, you want more mass than that.

I appreciate the replies to my situation. I understand the logic of what you are saying, gritres. My hope is that driving down further will work and if I have to put the pump at a lower level, that would be fine with me, as I have four grown sons coming over for the 4th weekend who are all strong and able (and willing) to help with this project. Thanks for the added advice!

just one other thing, you're never going to get serious flow out of a 3 foot driven 1.25" well so hopefully the 2-5 GPM is what you're aiming for