My automatic pool leveler's walls (original from 1978) need replastering. It also has a crack around the top that small roots have forced their way into the unit. I put a cork in the pool orifice and have dried out the area, but I would like some advice on the best product to use to resurface the walls and fill the crack. I purchased a 3#container of Leslie's Patch-It, but am not sure this is the right product to use. Any suggestions would be very welcome.