OK, let me give this to you straight, no platitudes nor attitudes.

You certainly have a 'ground water' issue, it's the ebb and flow of that water that caused your need to repair the bottom. Over the years the water flowing through the vercon base has eroded the crete out of it and will do the same in minutes on a fresh mix, as opposed to the years it took to wash out the set floor.

I had hoped your installer had put in a well point you could tap onto to keep the water at bay while you repaired the floor and dropped the new liner, but apparently not.

What I think will serve you best is excavating the hole I mentioned and installing the sump pump. With seeping ground water, if it's only at the floor of the hopper, you could probably get away with a ~ 6" deep hole and 2" of gravel under the sump pump.

You are worried about digging a hole in the bottom of a pool that has already washed out. If you don't, the patches you make will wash out before the new liner is set.

With the sump pump, you can keep the water at bay while you patch all the washouts, let them set and do the sweeping. Then you drop the liner in the shallow end and run it out to the deep end (**** if you pull the liner over the pump - put a piece of cardboard over the top of the pump, it gets HOT and can burn a hole in your liner!!!!!) When the water is imminent, pull the pump, fill the hole with gravel to ~ 1" below grade and patch it with hydrolic cement [* there are a few tips and tricks for this that I'll share, if you need me to].

Do you have a main drain? If so, there are other things you'll need to do when you start filling the pool, like installing and cutting it out.

It seems to me, and I may well be wrong, that you're planning a pool party for the 4th. In the long run, you'll be better off properly repairing the pool and dropping the liner, as well as coming up with a permanent solution to the ground water issue.

Just my $.02