I would suggest getting an inground pump because they are usually easier to open. I have a pool the same size as yours and when I replaced mine, I bought a full-rated 1/2 hp inground pump for my AG pool and it has been fine. (Chose that one based on the recommendation of my fellow mod Poconos who is our resident pump expert.) Be cautioned --- the pool store will try and sell you a bigger pump than you need! They will probably also try and tell you that you can't use an inground pump on an AG pool and that it is NOT true. That's what I am doing!