As a GC for many years Ive been in this stomach turning situation too many times...someone turns out a so-so job and asks for all his money. Usually I am in the middle between him and you and frankly at the end you have to look at what you got and whether it is servicable and what the imperfections are worth to you....29 years I have been negotiating these things and (touch wood) never had to be in court or pay ten cents to a lawyer...no contractor or customer is perfect and no pools are perfect.....you just want to maintain a good relationship with all parties if its possible. If he's talking about coming back to spray epoxy over the deck he sounds like a guy who takes responsibility. He needs to be given every opportunity to remedy his work. You are really not allowed to break the contract and hire someone else to fix it unless he has been negligent and refuses to discuss remedies.

I hope you and he are people of good faith and the couple of things at the end can be worked out. I can really be an SOB on the job when I need to be but building my own pool has been a humbling experience and I am living with some imperfections and still really enjoying my pool. I have to be honest....as a contractor there are so many, so many ways to cheat a customer with poor workmanship that the color of the sand sounds minor if he did an excellent job on everything else. BTW I wonder if down the road you would use cool paint on the concrete anyway? Also it makes me wonder if the references he gave you had any problems or do they still have a cordial relationship with him and continue to refer him? The serviceable life of the pool and the cost of ownership over time are significant issues here.

Best of Luck