I don't know if your tree will recover but pull out the fertilizer stakes. They aren't helping at this point but may hinder recovery. Fertilizer stakes over-fertilize the roots near the stake and leave the rest of the tree unfertilized.
If the chemicals in the hot tub were still strong, there's a good chance your tree got over-hot tub chemicaled. Was the water still hot? That would make it even worse.
