Pool/spa evaporation

[Drew80]

I'm hoping this is the right place to put this topic. I have a spa attached to my pool that seems to be losing water faster than the pool. As an experiment, I shut off the pump and closed the Jandy valve so that the pool and spa were isolated from each other (no water in or out). I let it sit that way while we were on vacation for 2 weeks, and the water level in the spa is now about 2 inches lower than the pool. The water in the spa is slightly warmer due to it being shallower than the pool, but I haven't heated the spa since starting the experiment.

Is there any way that the spa could be evaporating faster than the pool, or should I assume that there is a leak somewhere?

 

[duraleigh]

I suspect you have a leak in the spa....a small one, but a leak. I would let the spa continue down until it stops......that should help identify the location of the leak.

 

[Drew80]

Thanks Dave. I'll try that.

 

[Drew80]

Ok, so I've let my spa evaporate for a few weeks now, and the water level is below the jets. That tells me that my leak is suction-side. Which sucks. No pun intended.

Short of calling out a pro to dig up the concrete, what can I do?

 

[ping]

It could also be one of the valves leaking water back into the pool. Do you get air trapped in the pump basket when running the spa? If the pump basket behaves the same when running on the pool or the spa only, then your leak is probably just one of the valves. What was the reason for your decision to see if the spa was leaking?

 

[Drew80]

All the coping around my spa came unset, and it's the only spot around the pool that it happened. My theory was water expansion, so I isolated the spa from the pool to see if one dropped faster than the other. Sure enough, the spa level dropped faster.

My pool and spa are at the same height, so there's no way the spa could be leaking water back into the pool.

 

[jblizzle]

Could be either leaking in the spa plumbing or around the return jet in the spa (since you said it stopped just below the return).

 

[Drew80]

No, it dropped to about half way between the jets and the drain before I stopped the experiment. It has to be in the suction-side plumbing.

So do I have any options other than hiring someone to come dig it out? I REALLY don't want to do that.

 

[duraleigh]

I can't figure out your set-up from your description but don't be in a rush to dig.

Suction side leaks are almost NEVER underground

Suction side leaks are usually accompanied by air entering into the pump strainer basket while the pump is running.......is that the case?

 

[Drew80]

I just ran the pump in spa mode for about an hour. There is definitely air in the strainer basket. There was already some air in there because my skimmer basket overfilled last night and the pump started to suck in air (live oak tree is shedding), but normally the air escapes into the return jets after about an hour of normal operation. If anything, the amount of air in the strainer increased during my hour-long test.

It doesn't seem to make a difference whether I have it in spa mode or pool mode. The air in the pump strainer basket seems to be about the same or increasing slightly.

I should point out that basically none of my plumbing is above ground, so if there is a leak somewhere I'm not likely to see it.

 

[zea3]

Ok, check the usual suspects for a suction side leak: any above ground plumbing joints, drain plug on the pump pot, and the lid on the pump pot. You can test the joints by slowly drizzling water over the joints while the pump is running and watch for any water getting sucked into the joint. Make sure the drain plug on the pump pot is snug (careful not to over-tighten). Shut off the pump and remove the pump pot lid. Make sure the o-ring is in good shape and seated completely in the groove of the pot lid. Use silicon pool lube on the o-ring and put the lid back on and run the pump. If your filter has an air bleeder open it to remove excess air. If the suction leak is resolved the pump pot will fill with water.

Do you have any lights in the floor of the spa? Can you plug the floor drain to see if the leak stops?

 

[Drew80]

I've done a visual inspection of all the plumbing joints, and I don't see anything. I'll try the rest of your suggestions.

No lights in the spa. The drain has no threads, so I'm not sure I can plug it.