I am re plumbing our pool,DIY(me), the existing pipes are old and crappy.
I have two existing returns, approx 30mill black rubber hoses that run under the pool. I want to connect a poolskim. It's a rectangular pool with 180mill concrete walls.
Plan to core drill concrete wall, 180mill thick, and replace existing returns with one 40mill pipe. Is core drilling easy? What size hole? Where should I locate the new return? How far under the surface? What plaster mix should I use?