Advice on leak

[lumine]

Hi - new home with pool owner this year - thank you to everyone in the TFP community, have been trying to learn as much as possible by reading!
It is a weekend place, hoping to see if can implement TFP methods if only there on weekends. Currently have weekly pool service (lots of issues) but hope to change that next year.

Currently hoping for advice on a leak:
-Pool opening, water level was low approx 1 ft below skimmers
-Since then, have water loss - approx 3/4in per day. Did multiple 12hr overnight bucket tests with pump on and off (can't test through daytime when in use) - there's very minimal loss when pump is off, clearly losing more water when pump is on.
Does this mean the primary water loss should be assumed to be a pressure side leak?
-dug around the return line pipe into the gorund to the first 90 degree elbow and followed that line a little bit, did not see a leak and that soil was pretty dry. No wet spots seen

-have checked - no leak from backwash pipe, except for one particular episode - opened and cleaned multiport valve and seem sine.

The rectangular pool has a single suction side line leading to two skimmers on one side of the pool, and a single line leading to 4 returns on the opposite side.
-Pool co did a pressure test. They cut the skimmer return pipes, tested them and their conclusion was both sides are leaking. They may be right but just wasn't sure how reliable they are - twice their pressure rig set up wasn't seated well on the pipe and just blew right off and into the air while pressurizing, which did not inspire confidence. They also said they can't further locate leaks and they just recommended a big job, they'd dig up every single line in the ground to look for the leaks (includes dismantling pavers, patio all around pool). That definitely didn't sound quite right

Doesn't seem like main water loss is from within the pool, but have also tried to check, because the opening pool level was low:
-been told the main drain is dead, hasn't been used for the years and no one knows why. The valve at the equipment pad for that line is closed and taped shut. Just in case, I've dove and equipment off, unscrewed the main drain cover, did dye testing and no obvious leak seen. There was nothing in the bottom opening/(pot?) where in some online pics a hydrostatic valve would go - not sure if it's right but I put a screw in cap there that fit, and a winterizing plug in the side facing drain pipe. This made no difference it seems.
-liner is 3 years old. My own snorkeling/diving dye testing of skimmer plates, boxes, returns, single light, steps and any other suspicious site hasn't turned up anything obvious, maybe I'm just not experienced enough to detect anything.

From reading and researching seems like leak detection companies can use various tools/methods to listen with water/air pressure testing to much more accurately identify the site of leaks.
-Looking for any recommended leak detection services that will go to Suffolk/Eastern Long Island?
-in the mean time any advice for anything else to check or try?

Thanks!

 

[Texas Splash]

Does this mean the primary water loss should be assumed to be a pressure side leak?

The would be a correct assumption, but you also seem to have done quite a thorough job of your own trying to ID a potential leak of both the pressure and suction sides with no conclusion. I agree the previous leak detection company seemed a little suspicious and a bit too eager to rip-up the entire yard for more $$$$. I would also agree that it may be time to have a reliable leak detection company visit with deck plates and other sensitive listening devices. Problem now is you're on the clock with closing dates rapidly approaching. There is still one final option, and that is allowing (within reason) let the water level drop until it stops thereby showing where the leak is. Of course you can't let it fall too low and jeopardize the stability of the shell & liner, but you could let it drop to the returns at a minimum to rule out those plumbing lines. Oh, you didn't mention anything about a light. Did you check there?

 

[Texas Splash]

Oh, I almost forgot ........ welcome to TFP! Pool Care Basics

 

[lumine]

Hi, thanks so much for the reply and advice!
Going to try to see if can get a good leak detection company to help at this point (contacting American Leak Detection).
Thanks for the tip about letting the level lower - I'll have to see if will be able to possibly do that with the right timing available. I assume the pressure side leak will bring it down until it's below the skimmers, then I'd have to turn off the pump and see. Hopefully can get a good leak detection team in.
There is a light - I've tried myself to dye test all around it multiple times without seeing anything, haven't done anything else there. Unfortunately back when the pool opened I hadn't taken any good pictures where I can see the level it had stopped at, now really wish I knew the level.
Thanks again! Will try to post if the source(s) are found!