Pool And Attached Spa Losing Water. Suspect The Spa.

[bejpool]

I have a 33 year old Anthony 20k inground gunite pool with a small attached 300gal spa, level with the pool. (not raised) both the pool and spa share the pump and filter. Spa has a venturi system, with the venturi air line sticking out of the ground by the filter pad. There are 3 return jets and a main drain in the spa (main drain is usually valved off unless we're using the spa, which is seldom). The pool has 1 skimmer, 2 return jets. The spa has a small spillway which dumps water into the pool. Pump is a 4 year old Pentair Intelliflo VF which runs 24/7 at 15GPM/1 complete turnover a day (130watts). The pool is always clean and crystal clear with no debris on the bottom. I run the Polaris every night for 2 hours. (it's set up on the time clock)

Now that you all know the stats of my pool, I have a pesky leak that happens every year around the same exact time - around December and tightens up with no leaks a a month or 2 later and will continue to hold water all summer and fall until next time. I've done "the bucket test" every time this happens, and the pool can lose up to 1" in an 8 hour time period. I've had 2 leak detection companies scratching their heads and unable to find a leak. I've had everything checked: hydrostatic valves, pool lights, skimmer, plaster imperfections, Aboveground plumbing. Aboveground plumbing is tight and no leaks at all.

When the first week this December came around, it was losing 1 1/2" a day. I rolled my eyes, did the bucket test and started to keep a log trying different things: It lost water with the equipment on, didn't lose water with equipment off. Isolated off the spa and ran the pool, no loss at all. Isolated off the pool and ran the spa. This thing is dropping an inch an HOUR. So apparently, the leak is in the spa. I think I found it finally! It's definitley a return jet...or IS it?

My question is, is it possible for the pool and spa to lose water through the venturi air line? At times when the pool/spa is just running at 15 gpm, the venturi air line is full of water to about 8 inches down from the top of the opening of the pipe. When I call the leak detection company to check it, should I have them check that venturi line as well? If so, what's the best way to do that? Plug the opening and the jets?

[Pool Clown]

You mean they came out (and charged assuming a great deal of money) and didn't pressure test all the plumbing? Tell Ask them to come back out and pressure test the lines in question and gently remind them you do not wish to pay for that which should have been done the first time.

Funny how you have done a better diagnosing job than the leak detector. From your post, i would guess the spa return jet(s) or the air line. I'm guessing you told them that it only leaks a certain time of year. Hopefully it is still leaking when they come back out.

[bejpool]

You mean they came out (and charged assuming a great deal of money) and didn't pressure test all the plumbing? Tell Ask them to come back out and pressure test the lines in question and gently remind them you do not wish to pay for that which should have been done the first time.

Funny how you have done a better diagnosing job than the leak detector. From your post, i would guess the spa return jet(s) or the air line. I'm guessing you told them that it only leaks a certain time of year. Hopefully it is still leaking when they come back out.

So a quick update...leak is still there! The leak detection company came out again and pressure tested the return line and the venturi line to the spa. They pressurized to 10 psi then 14 psi. Pressure holds on all lines with no drop in pressure.

He then plugged the venturi line vent opening and ran the pump at full speed. The peculiar thing was there were sporadic puffs of air bubbles coming out of the center jet only, not the jet to the left or the jet to the right of it. (there are three jets total in the spa) Obviously, it's still sucking air from SOMEwhere.

Is it possible that this leak won't show under higher pressures? Usually, my pump runs at a lazy 15 gpm when I'm just filtering both the pool and spa. (about 3 psi on the filter gauge)

It really has the leak detection guy stumped! When he left, I set up the bucket test in the pool and had the spa/pool running at 15 gpm. In 12 hours, the pool and spa dropped over an inch! I shut the pump off and the level stopped dropping.

I called the leak detection guy and he's coming out again tomorrow. In his 15+ years of doing this, he's never seen anything like this.

I'm 99% sure it's the spa somewhere but where?? With the spa valved off for the past 2 weeks, the pool didn't drop at all in level.

I really need to find this thing! When/if I find out, I'll definitely keep you all updated.

[bejpool]

Found the leak! It wasn't the plumbing after all, but it was certainly in the spa. It was actually leaking through the light conduit in the spa. When the spa was valved in with the pool, it was just feeding the leak. How could something so simple be so overlooked by 2 different leak detection companies is beyond me.