Concrete pool leaks

[Vaporize]

Hello, I am new to this forum.

I moved into a Texas home last year with my first pool (~ 30,000 gallons - 10 yrs old). Initially, I kept watering the pool everyday but got tired of topping it off each day. I found out it was dropping ~ an 1.5 inches a day in the summer heat. I let the pool drain on its own to find out at which level it will slow down. I noticed it was draining slower and slower each day. By the time the pool was half the level it was dropping ~ 0.5 inch/day. The pool has been empty for the last 8 months. I have been lucky that the pool has not popped up. I finally cleaned the pool and discovered these the other day:

Here are the suspected leaks:
Picture 1 & 2 - Two main drains at the bottom of the pool.
One drain is sealed but the other drain is found to be open to earth/ground (I probbed it). Interestingly, when it rains, it still takes days for it to completely empty. Shouldn't it drain much faster if there is a big hole in the center? I have not opened the other seal.

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Picture 3,4 - Vacuum port spring cover is loose (spring not work). Can water leak through the vacuum port if the cover is loose?

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Picture 5 - Jet Eyeball
Can water leak out of the jet eyeball when the pump is off?



Other causes:
- About 5 fine, paper thin continuous crack that run down the wall to the bottom of the pool. Difficult to spot with pebble tech finish unless you scan your eyes a foot away from the surface.
- Leak from Skimmers/Pipes connected to skimmer.

I am thinking about filling the pool this week after closing the main drain seal and possibly fixing the vacuum port cover. Is there are thing else I should do before I put back 30K gallons?