We just bought a used pool. It measures 27 foot across. We measured in several spots and it was consistent at 27 feet. The lady we bought the pool from swears it's a 24 foot pool. We spoke with the company that it was bought from and they also show that she bought a 24 foot pool. It is now disassembled and I have no clue what size liner to buy. The walls were not noticeably bowed or leaning. Any suggestions on how to make sure I order the correct size? Any way to measure after disassembled?