So they ran a leak test yesterday and there is no leak anywhere so it's confirmed that water underneath pool was from the crack indeed. They plan to backfill hole today with pea gravel and start filling the pool to see how floor bulge reacts. I noticed this morning bulge has gone down more from yesterday. They will also be installing a pipe so if in future there is a leak they can connect pump to it and remove water (something that PB admitted his foreman should have done in the first place).