Main Drain Leaks Caused by Pool Resurfacing Contractor

[jak334]

A few weeks ago, I had my 15k gallon cement/block pool professionally resurfaced by a well-respected local remodeling company. The pool has been periodically resurfaced since it was originally constructed in the late 60's or early 70's. When I first purchased the house last year, I used epoxy putty to patch all the leaks I could find, which were primarily in the gap between the 5" tile line and the 15 year old marcite surface. I had also patched some small cracks around the mouth of the skimmer. After going through a few ounces of epoxy putty, I experienced no detectable water loss until my recent resurfacing.

On the final day of the resurfacing work, a younger guy began the acid wash around 5pm. He told me that it was his 3rd pool that day. He finished acid washing and rinsing the pool after nightfall. He began removing excess material that had fallen into the main drain pot by using a hammer and either a chisel or flathead screwdriver. I could hear the banging from inside the house. He finally left around 9pm, leaving the hose running to fill the pool.

About 30 hours later (early Saturday morning) I turned off the hose once it reached mid-tile line. The pool startup guy came mid-morning to treat the water, but noticed that the water had already dropped below the tile. He found leaks around the skimmer and patched them with epoxy putty, and he said that he would return Monday to treat the pool.

Monday came and the water level had already dropped below the return jets. When the startup guy returned, I explained how the acid washing guy had been banging away at the main drain, speculating if that caused the leak. He promptly checked for leaks was under the main drain cover, where he found a thumb sized hole in the bottom of the concrete pot and remnants of a failed patch. The startup guy patched the hole with hydraulic cement and came back the following day to finally startup the pool.

The water level seemed to hold steady for about a week or so until this past Thursday when I woke up to air bubbles coming out of the return jets from low water in the skimmer. I had the startup guy come back this morning to check for more leaks. Sure enough, he found another leak in the drain pot right next to the return pipe. He patched it with epoxy putty and told me not to run the pump for the rest of the day while it cured.

I asked the startup guy his thoughts on why the acid washing guy would be banging so hard at the main drain. It turns out, the acid washing guy thought I had a plastic main drain, and that he was removing excess hardened material from what he figured was a plastic drain body. Instead, he chipped a hole in the concrete pot creating the leak(s).
Even though the second leak appears to be fixed, I don’t feel confident that more leaks won’t form as a result of the concrete damaged caused by the acid washing guy.

TLDR: Resurfacing company damaged my concrete drain pot and leaks appear to be forming. What is the right way to repair the main drain pot so that leaks don’t keep happening?