Cannot be answered with only these measurements. You need to specify what shape the pool is. Also, for a rectangular pool, the length, width and depth are needed. For a round pool, the diameter and depth are needed.
Zero gallons. No gallons can fit into a plane, no matter what units you are using, since gallons are units of volume and must be expressed in three dimensions. Now, if you were to talk about a pool of 18' (that little ' denotes the measurement unit called _feet_ in standard English) by 52' by perhaps 10' deep, we'd have the ability to calculate an answer. Help us to help you.
25,000 Gallons
161,280 gallons.
10 gallons
2000 gallons
It depends on the size of the pool!
It depends on the size of the pool but 20,000 gallons is pretty common.
Assuming your pool is round about 800 gallons.
264 gallons is the max if it's a blow-up pool.