I have a gunnite, in-ground, 30K gallon pool. It has a 1.5 HP pump, the filter is the kind that takes powder and needs backwashing once in a while. I Just replaced pump that was 1HP because it was old (the breaker kept tripping when it started, and it was making a loud noise), and I wanted more pressure through returns. There are three returns and one skimmer with a basket and four chlorine pucks.
I'm losing water such that when I run the filter I have to run a hose, and have to plug the returns to avoid the loss. I know that the returns are pulling because I've put food coloring next to the jets with the pump off and dye gets sucked in. I've plugged all returns and tested each individually: with the other two plugged I open one, hold my hand over for a minute then do the food color test. Each pulls equally hard. I've dug out the dirt by the pump and there is no leak under it, so it's in the ground somewhere. How I can narrow my search to avoid digging up the whole pool?
The pool is surrounded by a sidewalk so I'll probably be breaking it up so I want to be certain.
I know the depth at which the leaking stops, and it's at least a foot above the returns. So it seems to me that the leak is not where the jets connect to the pool wall, which seems to be the most common place to find them.
I'm trying to devise a way to shove something into the jets that will stop water from going past, then doing the dye test at the next jet. That way I could narrow my search.
Any ideas about any of this?