bottome = bottom. Sorry.
The pressure is from the water, from the inside pushing out.
Do you have one of those flat bathtub stoppers... that might work for a bit.
RTVV silicon or caulk
dense foam under concrete or spent uranium block.
Make some sandbags (plastic garbage bags with some dirt would work in a pinch). Put each one over a hole. I may not stop the leak, but it should slow it down.
The first thing I would do is drain the water. Chances are you’ll need it dry to patch it effectively.
Very simple solution, you’ll wonder why you never thought of it yourself. Leaking from the bottom, right? Just tip the whole pool upside down, and I think it will quit leaking from what was the bottom.
Meanwhile, try the duct tape inside. No it will not stick, but water pressure may force it against the holes and slow the leak.
O, RTV on the INSIDE. IN the water. Get in and smear it around the leak area in quantity.
But you will be replacing the liner and the water.
You’ll need a vinyl pool repair kit. You can smear the adhesive on the patch and apply it to the submerged hole.
Nuke it
Mark as best you can where the leaks are, then drain out the remaining water. Duct tape on the outside is pretty useless; the water is under too much pressure. Duct tape (or foil tape) on the inside at the points of leak would help, but as mentioned it should be dry when applied so it can stick.
Sorry, bro but if the vinyl is thinning that’s all she wrote. It’s probably thinned-out everywhere. Possibly too much chlorine.
Declare your yard a wetland, then apply for government funds.
Vinyl liner
Buy vinyl patch kit containing patch and glue. The glue will work underwater. First find the holes. Put on a diving mask for easy viewing. Put glue on patch above water. Submerge and slap it on the hole. Easy peasy....fixed.
Home Depot or Lowes can sell you sealant that WILL work UNDER WATER.
One is a black gooey substance, the other is a two part epoxy ‘clay.’
Either WILL fix the leak.
Just put a piece of vinyl over the holes. The suction will seal the holes. Then go to Walmart and get a patch kit. Might work until the season is over. If the liner is truly thin then you drain and replace in fall.
If they can't help you....call your local water authority. The guys will love it.
That's an all too common occurrence. I've yet to hear of any leaking from the top........
Sounds like you're going to have to drain the pool and locate the leak then patch it......