I live in Cherry hill New Jersey. I am currently considering getting a fiberglass pool and was sightly discouraged by the sales rep claiming that fiberglass pools can shift and no company guarrantees against that. Is this true or does it depend on installation?

I'd put his words to a challenge, call 2 more installers and ask about their warranty. Sure, anything can shift but proper installation can keep that to a minimum. Once the excavation is done it must be clean with no loose fill in the hole, then a sand base is laid. Leveled and compacted. Proper installtion is very important since the pool will weight many tons once filled.