Money Pit Part 1 - The Leak
Summarizing is not my longsuit, but I'll do my best.
I've read the leak detection pool school article and so many leak threads that I am totally confused about what means what anymore.
We closed last year with a pretty hefty leak. The plan was to watch the level, and fill as necessary thru the winter. I never had to do that because we had a very wet winter.
Opened the pool a few weeks early to get a jumpstart on the leak, taking advantage of cold weather to have longer pump-off times.
This is a project pool that I'm desperately trying to get thru the summer while we tackle reconstruction ideas (that'll be another thread or two!). It's got an older, patched vinyl liner over what appears to be concrete or concrete block walls, sand or vermiculite floor, with a Trojan (?), white plastic over wood coping. One skimmer and two returns - very simple plumbing.
Filled up after opening, started the pump, and watched the levels drop again. Turned off the pump and started tracking the drop.
Pool held below skimmer and above closed returns over winter.
Level drops dramatically with pump on filter or recirc: average around 1/4" an hour for both
Drops less with pump off, but still more than evaporation: average around 1/4"-1/2" every 12 hours (I have 11 days worth of more detailed info about plugged/open status for pump-off testing. Some minor differences but nothing nearly as dramatic as pump-on vs. pump-off)
Essentially no evaporation; bucket level didn't drop at all over most of these days. In fact, my bucket level goes up some days! We've had the coolest spring in ages here in KC!
Pool drops below plugged skimmer and skimmer face plate; plugged skimmer holds water (i.e. no cracks in skimmer body?)
My interpretation of the dye test showed both returns sucking in dye through the eyeball, but not around the return itself.
Backwash line has a valve that is normally closed unless backwashing - don't know if that's relevant, but thought I'd stick that in here. I'm thinking that means it's a double-secure method of not having the multiport leaking out the backwash pipe???
I have a fabulous detailed spreadsheet that starts on 4/19, and a pool covered with pencil marks and tape strips. I turned off the pump once the water level got too low. I've let it drop 2" below the skimmer but it was still above the returns. It may have continued dropping, but I needed to fill and filter because we finally had a few warm days.
At this point, I'm thinking I have multiple types of leaks, given the behaviour, but am desperate for input. I've tried any number of combinations of plugging things and running things, just in the name of gathering data to share. I feel very unfocused!
So, there's my poor attempt at summarizing!
(I need to update my signature, I see. The heater is gone, and the sand filter was replaced with a new, identical model.)