In-ground cement pool. I have plugged all of the pipes (suction and return) besides the main drain suction hole and the pool is still leaking. I took the light out and saw that they had previously used epoxy on the light niche. I put an entire new layer of epoxy all around that. I then unscrewed the main drain (which was very fun considering that one of the screws was stripped). The main drain is made of plastic. There is a 2" pipe on the side of the main drain that is open. There is also a plug down there that I believe is the "hydrostatic release valve" which as I understand it needs to be opened when pumping the pool because it will allow water to enter the pool and prevent the pool from floating like a boat if there is water in the ground higher than the bottom of the pool.
In the main drain there is also this weird cement sand like mixture that was slathered along part of the drain's side, I guess to stop a previous leak. Some of it has fallen off and is sitting at the bottom of the main drain. I put a new layer of epoxy over this as well. I tried to dye test the light area and the main drain area but it was all unsuccessful.
The pool is still leaking. It has not yet reached the pool light so I cannot 100% rule that out. The water level is currently an inch or so above where the hole for the pool light starts.
This is my first pool and I had been refilling it liberally, finally realizing this was abnormal and not evaporation from the Florida Sun. The leak has been about an .75inch/24 hours for quite awhile, maybe a month. I have noticed that my sprinklers (well) have been very strong so I suppose there is a good bit of water down there. Tonight I ordered a 2" rubber plug online that I will use to plug the main drain. Some questions:
How big of a risk am I running the pool pops out of the ground? Do I need to unplug the "hydrostatic release valve"? What do I do from here I have no idea where the leak is coming from.