Leaking pool, OK to run below skimmer?

[ehuesman]

Hi everyone,

A little over a week ago, I noticed my pool had a leak. I'm losing about 5/8" each day! I've tried a few things, which I'll outline in a post below for anyone interested in helping me troubleshoot the leak, but the main point to this post is I'm trying to find out if it is safe to continue running my pump when the water level is below the skimmer entry. The water level in my pool is already several inches below the entry for the skimmer, and it is getting close to the return outlets.

I've contacted a leak detection company, but their first appointment isn't until November 24th! I have no interest in keeping my pool full until then, primarily due to the hefty fines imposed by my city for water usage (due to the California drought). Even though I don't want to keep the pool full, I still want to keep the water sanitary. Mainly because that is required by the leak detection company, in order for them to do their job (divers don't want to get in a slimy pool).

I imagine the answer to my question depends on how the suction lines are plumbed, and unfortunately I'm not 100% sure. I'm also a little confused on how to figure that out. Here is what I can tell you: I have two outlets in the bottom of my skimmer. When everything is working normal and the pump is on, I can only feel suction from one outlet. From what I've read elsewhere on TFP, that is normal and the other outlet may or may not be plumbed to the "main drain". I also don't know what my "main drain" would be considered, because I have two large drains in the floor of the deep end of my pool, AND two large wall drains, also down towards the deep end of the pool. I also have suction line for my pool cleaner, which comes out of the wall like normal.

I have the ability to plug one or both holes in the bottom of my skimmer, but I wasn't sure if I should do that. Would it be okay to plug both holes, and just let the pump draw water from the suction-side cleaner line? I have an adjustable valve where I could completely shut off the skimmer, but didn't know how safe "full suction" would be for the cleaner line. If I don't plug both outlets in the bottom of the skimmer, and assume that second hole is plumbed to a "main drain", will that continue to work once the water level in the pool drops below the level of those two outlets?

I'm not the original owner of the pool and home, but I do have a few pictures from when the pool was being constructed. They are not the best quality, but I included a few pics in case it helps anyone make sense of my set up. I'm not sure if the four drains would be all tied in to one line, that then ties in to that other outlet at the bottom of the skimmer, or the outlet would only be plumbed to one of the drains, and the other drains would just be connected to the pump on their own. What would a "normal" set up be?

Thanks in advance for any help provided!

- Eric

 

[ehuesman]

Steps I've taken to find leak:

(in case anyone has any ideas to save me the $450+ the leak detection place is going to charge)

I isolated the leak to the pool by closing off the valves that lead to the spa at the pump. When I do that, the spa is only losing to evaporation. I know this because I've marked it with a grease pencil and it takes days for any measurable amount to be gone, especially with the bubble cover on. With the spa isolated, the pool continues losing about 5/8" a day.

After isolating the problem to the pool, I took out those return fittings and plugged the pipes with rubber expansion test plugs. I also bought two threaded ABS plugs that fit the two threaded outlets in the bottom of my skimmer and screwed those plugs in. The water in the pool continued draining at the same pace after plugging these things up. The expansion plugs are from Home Deport, and they are not as good as what is normally used by folks that have to winterize their pools (because the depth of the rubber part on my HD plugs aren't as deep as on those types of plugs), but I figure even if the seal wasn't perfect it should have at least slowed the leak, and there was no measureable difference at all.

The water level has continued leaking, and is past the bottom of the entry hole for the skimmer, so water cannot enter the skimmer from the pool. I think the water in the skimmer might still be going down slightly faster than just for evaporation. It's hard to tell, because I can't get a good view down the skimmer, but the water left in the skimmer is definitely not going down near as fast as the water in the pool. My guess is maybe I could screw the test plugs a little tighter in the bottom of the skimmer, but I don't want to over-due it and screw up the skimmer. When you over-tighten threaded plastic fittings, it's the threads on the female end that normally get ruined.

After all that, the water is now past the tile line, and there are no visible cracks in the plaster anywhere. I figure the leak has to be in one of the four drains (two on the floor and two in the wall), or the pool light - which I know is a common culprit for leaks. I bought some leak detection dye, and took the pool light out, but I was unable to detect a leak in the housing. I'm not 100% in my ability to do that though, especially since I don't have real scuba gear, and my jerry-rigged outfit (don't ask) wasn't really working. It was at this point I decided to call the pros.

 

[Divin Dave]

Hi,
I dont think I can help with finding the leak, but its not OK to run the pump with water below the skimmer without plugging it.
If you dont completely plug the hole in bottom of the skimmer, the pump will suck air through the skimmer pipe, and loose prime.

Im assuming of course, that your main drain is plumbed directly to the equipmetn pad, and not into the bottom of the skimmer like a lot of them are.

 

[ehuesman]

If I keep both holes in the bottom of the skimmer plugged, should I also close the valve at the inlet side of the pump that leads to the skimmer? I have a 2" line that leads to the skimmer, and a 1.5" line that leads to the pool sweep, with an adjustable valve between them.

I'm just not sure if the 2" line, in addition to going to the skimmer, would also be plumbed to one of those four drains. What is a "normal" set up? And on the other hand, would it cause any harm to completely close off that 2" line and just run the pool sweep line? I have no way to reduce the power of the pump, as it a single-speed 2HP pump. I just don't know enough about plumbing to know if that would be too much suction solely for the pool sweep line.

Im assuming of course, that your main drain is plumbed directly to the equipmetn pad, and not into the bottom of the skimmer like a lot of them are.

I just saw this part of your reply. There are only three lines that lead to the inlet side of the pump. One of those goes to the spa side, and the other two go to the pool side, and are the two lines I described above.

Thanks for the reply and help!

 

[Divin Dave]

Hi Eric,
from your description of having 2 holes which are plumbed in bottom of the skimmer, and the plumbing at the equipment pad, it sounds to me like the drains are plumbed into the bottom of the skimmer. Or at least some of it is.

Here is what I would do if I were you.
Leave the rubber plugs in the skimmer and at the equipment pad, turn the valve to close the skimmer. That way the pump wont be able to suck the rubber plug in the skimmer into the pipe.

Then turn on the pump and see if it has water flowing into it.
If the pump runs dry, then all of your drains are plumbed into bottom of the skimmer.

If the pump has water running through it, then at least some of the drains are plumbed to the pad. Then go to the pool and put your hand over the drains in the side, and see if you can feel any suction.
If you can feel suction, then go back to the pad and close one valve, then check suction again. This is about he best way to isolate which valve operates on which line.

If can get suction from either the sidewall or main drain, then you should be able to run the pump with the skimmer plugged.

If you can put either rubber plugs or threaded plugs in all of the lines in the pool, including the retuns, and water is still dropping, then likely its the light thats leaking.

You can to that at the main drains too, by taking off the drain covers.

And i wont ask about your home made scuba gear if you dont ask about mine!

 

[ehuesman]

Well I figured out what the two drains are for on the wall...they're the intake for the arc waterfalls. Not sure why it didn't come to me before, but oh well.

In regards to running the pump, it wouldn't prime with the skimmer plugged up. It would suck as much as it could through the sweeper/cleaner line, but it just wasn't enough to get complete prime. I'm worried that is too much strain on that single smaller line. So in the meantime, I'm just running the arc waterfalls to help circulate some chlorine and I'll just have to do without any filtering for now.

On the leak side of things, I took the covers off of the two main drains and it looks like I should be able to plug those lines and see if the pool keeps losing water. There is some plaster/concrete built up around the pipe (sloppy work), so getting an expansion plug to fit tight might be an issue. I'm searching online right now.

Thanks again for the help.