Missing chunk repair in a concrete pool

[consoleman]

So I was getting out of the pool and something felt odd where i was stepping. I look down and It seems there is a big hole in the pool. The pool floor has cracked and brittled into pieces. Now I can see the shell (i believe of the pool)

After inspection It seems there was a crack down there and maybe weakened the top layer cause it to crack and brittle. How can I fix this? I will post pics

 

[consoleman]

You can see here that the top surface sort of collapsed. Im currently draining the pool. The collapsed area is maybe 2.5 inches long, while the crack is about 5 inches long

 

[consoleman]

Update: There seemed to be a crack that I never saw. The water penetrated the plaster and caused the plaster to lift up sort of like a mosquito bite. Once stepped on it broke due to no support since it had lifted off the concrete shell.

I ended up draining the pool and I broke off all the lifted up parts by knocking on the plaster with my hand and listening to a hollow knock. If hollow I broke that part off and ended up from a 2" hole to a 7" hole. I then patched with leslies patch up mix (i looked for ez patch 1 but leslies doesnt carry it). Once patched I let it sit for 24 hrs just to be sure (the product say 10min and can also be applied underwater as per the instructions).

I noticed the paster was thinner on some sides of the hole. So i am currently looking into a renovation.