I was thinking, if there was a leak at the descents then I should see a drop in my water level. Minimal rains this past winter and water level hasn't dropped. I've run the descents minimally but will open them up and run them full throttle for the week. my pH will rise up even more than usual, but that should give me an indication if there's a leak from them. ThanksYou’d have to pull up the pavers to see the condition of the base.
Or a leak detection company with very specialized sounding/infrared equipment.