Sounds like the pool issue is well in hand but the disclosure part wasn't fully addressed. If the seller knew of the problem and failed to disclose the issue you may have recourse to go back on them. You might be able to argue they attempted to conceal the problem with the cover. It depends on the laws in your area. It will be a PITA to pursue but it may be worth looking into.
Do you have any kind of new home insurance policy?
Do you have any kind of new home insurance policy?