Hi, Ron,

It is quite difficult to repair concrete decking and get a decent aesthetic look. The old WILL NOT match the new areas, the textures will be different, etc.

Because of the multiple issues you have, I would get a price on busting it out and replacing the entire deck. If the pool is more than 5 or so years old, the dirt under the decking may be settled by now (that's the cause of the cracking) or, if you remove the existing deck it can be carefully compacted so the new will hold up.

That'll be a pricey fix but at least worth consideration. It sounds like your serious about getting a nice pool back under control so it may be worth it.