8249 US gallons, approx.
About 17,950 gallons.
280.298 Imperial gallons
To fill this pool to a depth of four feet you will need about 7,646 gallons of water. If you decide to fill it to three feet deep, the gallons decreases to around 5,735.
250 ft3 = 1870.13 US gallons
If the pool is a constant 9 feet deep the total volume would be 48,600 gallons. However, if 9 feet is only the deep end and the shallow end is 3 feet deep, the gallons changes to 32,400 gallons.
A maximum of 1,196.88 gallons of water.
1869 Imperial gallons, approx.