False Air Leak / Severely Clogged Skimmer Line?

Mar 15, 2015
18
San Diego, CA
Hi, all! First, let me preface my first post by thanking everyone here for lots of help last summer when I first started pool maintenance on my own. I hadn't registered or posted, but lots of previously-addressed questions were exactly what I needed to learn about pool maintenance. I come to you now with a few questions, seeking advice directly...

I'll list some details about the pool first, since I know that's the most helpful first step:

It's an in-ground, gunnite pool, about 10,000 gallons. I live in San Diego, California. The pool has some cypress trees right next to it, and it frequently gets debris from the trees in the water. The pool has one floor drain, and one skimmer. The pump/filter sit about three feet above the water level in the pool, due to the backyard having a slight hill. There is only one pipe that comes up from the ground/concrete into the strainer basket, and has no valves inline between the ground and strainer. The filter is a Cartridge-style filter, installed about three years ago, which replaced a stainless steel DE filter tank. There is a valve after the filter, which diverts water to a bank of black plastic solar heater panels, or directly back to the pool. There are two return jets, which are just small plastic pipes, and don't have any kind of valves to open or close them.

Okay, so on to my problem. About a week or so ago, I noticed that the pressure gauge on my filter was much lower than normal, only 3-5 PSI. I then noticed that the strainer basket had air in it while the pump was running, creating quite a large 'tornado' of air/water. When the pump is off, the strainer pot is almost immediately filled with water, with only the very smallest air bubble at the top of the clear lid. So, I suspected an air leak, between the intakes and the pump. I removed the lid from the strainer and cleaned the lid gasket as well as the mating surface of the strainer. The gasket looks good - no bulging, not misshapen. With that replaced, I still got a lot of air in the strainer pot when the pump is turned on. So, I tried the method of turning the pump off and looking for a spurt of water, found nothing. Tried applying shaving cream to all the plastic joints, and found no leaks (to be fair I couldn't see underneath the pipes as the whole thing is inside a small wooden house and I don't have a proper inspection mirror.

So, unable to find a leak I kept googling with different search terms to maximize my results, and I came across a comment that a clogged skimmer line can mimic the symptoms of an air leak - namely, the air appearing in the strainer pot. Since I was unable to find a leak, I decided to look into the possibility of my skimmer line being clogged. I read that using a drain cleaning bladder could push clogged debris back out of a skimmer line, and that for especially stubborn clogs, the drain bladder could be applied first from the strainer, back towards the pool, and then applied from the skimmer towards the strainer.

I bought a rubber drain bladder from Home Depot and hooked it up to my garden hose and got it situated in the strainer pot, nozzle jetting out to the skimmer. I turned it on, and got water flow (though I'm not sure how much) and some bubbles coming out of the skimmer. No debris came out. So, I thought perhaps this is a stubborn clog, I'll go ahead and reverse the drain bladder to try and work the clog free. Here's where it gets interesting - I put the drain bladder in the skimmer line headed to the strainer, and turned on the water. The bladder filled up and wedged itself in the pipe as it should, but, at the strainer, absolutely no water flowed from the pipe. My first thought was that perhaps the line was connected somehow to the floor drain, and that the water jet was simply not impacting the clog. I shut the water off and went to remove thedrain bladder from the pipe, and discovered it was stuck fast. I simply could not remove it, and the bladder was still inflated. That tells me that the water pressure indeed found a clog and was completely cutting off flow from the skimmer to the pump, and that the only place it could be getting water from was the floor drain, and, in theory, not able to draw enough water through only the floor drain creating the air bubble in the strainer.

I had to remove the hose from the wall in order to release pressure on the drain cleaning bladder so that I could remove it from the skimmer. So, now that I've written an entire novel, my question is, does any of my reasoning hold up? Could my skimmer line be so clogged that it's creating what looks like an air leak in the strainer, and the low pressure in the filter?

If so, should I then find a pool service to use CO2 to clear the clog? I tried using the bladder from the strainer a couple more times with no debris being unclogged.

I very much appreciate any help/advice! I'm at a complete loss (I think. I might be on the right track, which is what I'm hoping to learn).
 
:wave: Welcome to TFP!!!

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Do you have 2 holes in the bottom of the skimmer? Did you try running water in both of them? Just want to make sure you were not trying to push water through a capped line.

If there are 2 holes, usually one is plumbed to the floor and the other to the pump. Assuming the line is not capped, it sure does sound like something is clogging the pipe. I might be inclined to run it some more in the direction you were getting bubbles and see if anything comes loose.
 
Thank you all for the welcome! (I really should have joined long ago!) Jblizzle, to answer your question, yes there are two hole in the bottom of the skimmer, and I'm almost positive you're correct, one leads to the floor drain and one to the pump. I didn't run the drain bladder in the other hole (although it couldn't hurt just to double check). I think I will try running the drain cleaner from the strainer again tonight, and just try that for a while. What I didn't do was to try using a tennis ball to temporarily stop up the hole in the skimmer, to try and build some pressure and 'pulse' the clog loose. I think I'll give that a shot tonight, if I can find a tennis ball somewhere.

Here's a related question: since the pump is (apparently) not getting enough water, should I not run it for the time being? (I know - this is a terrible thing, and will probably end up with a green pool if I do this for long) But, I assume I could overheat/burn up the motor if it keeps running like that? I think if I can't clear the clog by running the drain bladder a few times each night for a few days, it would be safe to assume I need to call in a professional with tools this weekend.
 
Hi twitehouse,
Welcome to TFP!

From your description, it seems as though the pump is priming, but you just have teh whirlpool and bubbles in the strainer? If so, you should be ok to run the pump.
However if the pump looses prime and continues to run, then thats when you get into the trouble with it.

As an alternative to running your pump and avoiding an algae outbreak... IF you have a robot cleaner or a pressure side cleaner, you could dose the pool with liquid chlorine, and let your cleaner mix it up in the water until you can get your plumbing problem fixed, hopefully soon.
 
Hey guys! Guess who's clog got fixed tonight!

I couldn't find a tennis ball around the house, so I improvised with a tightly balled-up sock and a plastic bag... I hooked up the drain bladder to the strainer and turned the water on just a bit. Then, I pushed the sock/bag combo down against the skimmer hole and held it there for about ten seconds before releasing it and letting the built-up pressure come rushing through the pipe. I didn't seem to get much at first, just a couple very small leaves and debris. Then, I got a small rock! Maybe .75" across or so... I got that out of there and kept up the routine for a while. All in all, I got two rocks and a couple "acorns" (I don't know what they're actually called, but the come off the Cypress trees and are about acorn-size) out of there, along with a seashell... I have no idea where that came from. I figured I would try putting everything back and see what happens. Success! The pump primed just fine, and voila, the "air leak" was gone, no more tornado in the strainer and my filter pressure gauge went right up to 10PSI! Pump nice and quiet, too. What a relief!

No need to spend money on a specialized service, no green pools and some self-satisfaction to boot.

Now, my next steps are to figure out what to do about my solar panels... That will be another post in a different area, I believe.

Thank you guys for the advice!
 
I (stupidly) don't have a leaf catcher inline with the floor vacuum. Finances are/were tight, so when I got the thing I reasoned that I would just use it when there wasn't any visible debris in the pool. Apparently, that wasn't quite good enough. Strangely, I haven't used the vacuum at all recently, (as in, several months) and this issue only began a week or so ago. It's quite likely I'm to blame for this clog, but I'm mystified by the timing. Alas, the shell was just an ordinary little thing.
 
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