I am purchasing of a home in Florida there was a patch on a crack in the pool which the seller agreed to fix in the contract

You’re in a tough spot.  The realtor could be correct; however, it all really comes down to how “fix” should be legally interpreted.  Is a patch enough to be considered a “fix” and therefore you agreed to it?  Or, as you (and I’m sure most buyers would) see it, fix means a permanent fix?  Of course, if you do the walk through and the pool level is down, arguably, it doesn’t matter because the patch is not working as a temporary or permanent fix.  Practically, here’s the issue – if you back out due to the pool, your contract probably states that your escrow goes to the seller (and may even allow for some other damages).  That said, there’s a consideration as to how much it is going to cost to fix the pool.  Ideally, you would be able to negotiate this fix into the contract.  Keep in mind, too, that the realtor wants the deal to go through because even though he’s “your” realtor, he probably gets at least half of the commission.  Legally, keep in mind that to “win” this argument means a lawsuit and having the court agree with you that the Seller failed to live up to the contract (breached it) and therefore, you’re owed your money back.  I would advise contacting a local real estate attorney to review your contract and discuss the details, and perhaps negotiate a resolution for you.