Concrete pool big leak

[joejoe]

Leaked down last fall below the return lines so I pluged the holes for the Ohio winter. To my suprize it was full to the line on the skimer this spring so I run the pump a few hours. The water started going down overnight and in 5 days I lost 12,000 gallons of water to the same place it was last fall. It is now below the returns and the light pocket the top 2"s is out of the water. I pressure tested the lines and they hold 16 pounds pressure. Will the leak be in the light housing as that is where it stoped going down? I have a hard time with it filling up over the winter then leaking out all that water in 5 days.

Help in Ohio

[Guest]

Sound like light niche or coduit.Need to go under water with mask on and check it out with dye.