Trying to identify leak, decline slowed below returns

chunky · Jan 19, 2018

Trying to identify where a leak is most probably located...if possible Noticed pool level declining faster than normal about 6 weeks ago. Turned everything off and let water level fall on it's own. Rate of drop slowed considerably after it cleared returns. One caveat, and perhaps I should have plugged it, there is a dedicated vac port at roughly the same level as returns. I'm thinking I may need to plug returns, fill above that vac port to verify that there is not a leak in that line?

Does that make sense? I can't say that I noticed any unusual air in system when it was full and running with vac engaged, but maybe I just missed it. I would assume would be a clue in vac line. May need to just dig some more, but would like suggestion on how to isolate potential leak in return lines...if there is a way.

Thanks.

Jeff

Jimrahbe · Jan 19, 2018

Jeff,

I would plug the vac line and half of the returns... add water to get above the returns and see if the leak is still there.

If yes, then most likely one of the open returns.. Plug half of them and retest.. etc..

If no, then remove the plugs from the plugged returns and then plug the open ones.. retest...

How much is it leaking in a day? I use an old, clean, paint stirrer stick that I hold between the bottom of the skimmer mouth and the decking.. Leaves a nice water mark when removed, which I highlight with a pencil.. Then I retest the next day at the same time and make another pencil mark..

Thanks,

Jim R.

chunky · Jan 20, 2018

Jimrahbe said:
Jeff,

I would plug the vac line and half of the returns... add water to get above the returns and see if the leak is still there.

If yes, then most likely one of the open returns.. Plug half of them and retest.. etc..

If no, then remove the plugs from the plugged returns and then plug the open ones.. retest...

How much is it leaking in a day? I use an old, clean, paint stirrer stick that I hold between the bottom of the skimmer mouth and the decking.. Leaves a nice water mark when removed, which I highlight with a pencil.. Then I retest the next day at the same time and make another pencil mark..

Thanks,

Jim R.

Thanks Jim. I did the bucket test. Water level was dropping about .5 inch per day. Typically it was closer to an eighth of an inch maybe. Our spa level did not drop at the rate of the pool, so it was kind of easy to identify. I think I'll plug and refill. Keep digging around. I really need to isolate and eliminate the vac line from consideration, if that is or is not the problem.

swimcmp · Jan 20, 2018

If the water has dropped below the returns it is not the returns. Is there a light and is water still above the light or towards the middle of the light. Check the light conduit if so.

chunky · Jan 20, 2018

swimcmp said:
If the water has dropped below the returns it is not the returns. Is there a light and is water still above the light or towards the middle of the light. Check the light conduit if so.

I did initially suspect the light, but the water stopped dropping at the same rate once it cleared the returns. The light is still another foot or so submerged. I'm actually digging around the area anyway and the conduit is tracking with the pvc pipes. Bad thing is it's a diving pool so there is extra decking above the light and return on deep end where diving board is, so I'll need to tunnel in.

swimcmp · Jan 22, 2018

If you have the pump off and it is still leaking below the returns it is either the light or the main drain if you have one

blf212 · Jan 22, 2018

Try the light if you have one. Happened to me about a year ago. Thought it may be the return but the water line keep dropping. Call a pool guy out an it end up being at the light. good thing it got caught.

Jimrahbe · Jan 22, 2018

Keep in mind that there is a difference in "the water dropping" and "still having a leak"...

For example.. if the pool level was going down an inch a day before it got below your Returns.. then I would consider that a "leak"...

If, after it got lower than the Returns, the rate at which it was going down was reduced to less than a 1/4" a day... then to me that means the leak is most likely in a return lines.

Anything less than 1/4" a day is probably just normal evaporation..

If, after the water got lower than the Returns, the rate did NOT change, then obviously the leak is still there.. and somewhere below the Returns... As others have said, most liklely at the light.

Thanks,

Jim