I recently lost about 2-3 ft of water in about 1/2 a month with the pump off. The level has dropped below the light fixture by about 3″ and stopped. There is a side suction that remains under water along with the main drain. I added water to where it covers half the light and I have no leaks. I believe the suction line might be cracked and the water level is below this crack but I don’t want to turn the pump on as it probably won’t suck until all lines are full of water I did replace the pump to a 2 hp total from a 1 1/2 hp about a month before this happened as it died after about 11 years. I’ve plugged both drains, no drop, then unplugged one at a time with no drop.