Tom's pool leak

[TomAtlanta]

I posted here a month ago, then got very busy and had no time to think about the pool. When I first posted I didn't even know what to ask and wasted a lot of time, so now I am starting a new subject in which I will sum up what I now know is the important information.

I live in Atlanta Ga.
36 x 18 oval pool, inground, plaster pool.
3 hp pump. Sand filter
I recently bought this house as a foreclosure and I have no other info on the pool.
House was built in 1971 but I don't know if the pool is that old.
The main drain was plugged, so I assume there was some leak there.

I have a friend who works for a pool company helping me. He is a good person who I like and trust, but he is not a genius, which is why I am asking quesitons here.

When we took the cover off the pool it was like a swamp. Leaves had been rotting in there for a long time. The water level was down about a foot below the the top.

We raised the water level and measured it for 3 days. The water went down about 1/2 inch in 3 days, but we figured that was normal evaporation and not a leak.

The pump had been stolen or removed, and we put in a new 3hp pump.

We drained the pool and cleaned it and refilled it. It then started leaking, going down about an inch a day. My best guess is that when we cleaned it out we opened up some leak, but I don't know how. Turning the pump off did not slow the leak.

There are two returns. One higher than the other. When the water level got below the first return, the leak slowed to about half an inch a day. We figured there was one leak there, and one somewhere else, either in the light or the lower return. We plugged the lower return and the
water level continued going down but only about a third inch a day, so I assume there is a problem in the light. I don't know if plugging the lower return slowed the leak, or if it slowed because the weather is cooler and the water is lower.

When we drained the pool we found a spot in the bottom, about 6 inch in diameter, where the plaster was gone. I think this was probably caused by us. We used a pump to drain the pool, and I think maybe in the process of moving it around down there we broke the plaster, but I am not sure. We patched the spot using some pool cement.

What is the best course of action now?

Drain the pool down below the light, seal the light, raise the water level back to the top and see what happens?

It has gotten cooler here and I doubt we would swim again this year. Soon the leaves will start falling and I will need to put the cover on the pool, so the other choice is just put the cover on the pool, then take it off in the spring, and the water level will tell me exactly where the leak is.

Remember I am totally inexperienced with pools so I hope I have given the right info.

Thanks for your help.

 

[TomAtlanta]

One other thing. I bought this house because it was a foreclosure and a great deal. I had no interest in a pool and thought maybe I would just fill it in. However, when we got the pool open and cleaned I thought it was beautiful, and the first day I went out there and swam laps for exercise I thought it was the most wonderful thing in the world, so one way or another I am going to fix this pool. However, I am not wealthy and need to pay attention to costs.

 

[Bama Rambler]

I would clean it and cover it. Let the water level tell you where the leak is next year.

 

[Coffin Dodger]

So you noticed the leak got worse after you pump, cleaned and started it correct? Does your pool have a hydrostatic valve in the main drain? If so there might be a chance that the valve opened when the pool was empty, and when it filled to the point to have enough pressure to close the valve, debris may have settled between the seal and the valve top not allowing it to close all the way. Ive had to "pop" many a hydro valve in my time (popping it is just basicly diving down and pulling the top up and let the springs pull it down to make the seal) and it has saved loads of time searching for mystery leaks. If you dont have a hydro valve then I just wasted a lot of time typing

Another quick place to check would be the multiport spider gasket. They get old and the gasket deteriorates to the point where it starts diverting water to the wrong places. Say you are on filter and have a bad spider gasket, the bad gasket will allow water to sneak into the waste, backwash or any other port (you can see what Im talking about after youve removed the top of the multiport valve). One way to check really quick is to remove your backwash sight glass while the pool is filtering. If you see any water coming out of where the sight glass was (if no sight glass, check backwash/waste line), your spider gasket is bad.

BTW, Im curious, how big is your pipe size? If its 1 1/2 inch a 3hp pump might be a bit much. How large is the filter? A 3hp pump is loads more pressure on your lines as compared to a 1 1/2 or a 2 which would make the leak worse (and possibly easier to find). What kind of deck do you have? If you have wood or grass you can always let the pool run and take a long, thin metal stake type thing (at least three foot long) and start probing for wet spots along where the return lines go. BE CAREFUL! DONT SEND THE PROBE THROUGH YOUR PIPES!!! Just push it in as far as you can and then gently tap down the probe at least to the level of where the returns are in the pool. If you meet resistance and it wont go down anymore, you might be on top of the pipe. If you look at the return in the pool, aim for the outside of the fitting (along the side of the pipe). Then when you think youve got to a spot alongside the pipe, let it sit there for a minute and pull it out. If its dry or damp soil/sand/whatever on the end of the probe, its likely the leak isnt there. If you bring it up and its sloppy wet you are getting closer. Keep in mind also that water goes downhill so start next to the returns right where the wall and pipe meet. Again, if you have a concrete deck I just wasted some time typing again :|

This is very basic stuff looking for leaks but sometimes you get lucky. You can always make a pressure tester to test the pipes, Im sure your friend knows how to do that if hes in the biz. If he doesnt, I can tell you how. Its not difficult at all :-D

Hope some of this helps!

 

[grrltraveler]

What did you use to "mark" the water level with?

 

[TomAtlanta]

I've been away a few days. Thanks for your questions and your help.

Here are answers to your questions:

We replaced the spider gasket when we replaced the pump.
Pipe is 2" diameter PVC. Filter is a Hayward S310T.
There is a hydrostatic valve, but it is not in the main drain, but a few feet beside it. The main drain has been sealed, so I assume it was leaking.
I have a concrete deck.
I am marking the water level with a metal tape measure that I taped in place and put over the side of the pool.

My questions:

The water is going down much more slowly. It has gone down a total of 22" in 6 weeks, but has only gone down 3" in the last 2 weeks. Maybe this is because the weather is cooler and there has been some rain. Maybe there are small leaks in both returns and the light, and since we plugged one return and are below the other, it is now only leaking through the light. Maybe as the water level goes down there is less pressure and leaks are slower. Which of these makes sense to you?

 

[TomAtlanta]

Here is a better break down of how the water level has gone down.

For the first 9 days it went down about 1" per day, until it got below the first return
For the next 20 days it went down about 1/2" per day, until we plugged the lower return
For the last 14 days, it has gone down about 0.2" per day, or a total of 3" in 2 weeks. It has been cooler and there has been some rain during these last weeks.

 

[Coffin Dodger]

An *easy* fix for the light is to take it out of the niche, see where the wire goes into the niche, then take some butyl tape and stuff it in the hole and around the wire to seal any leak in the conduit. The butyl tape will conform to any shape you wish and is easily removable. Ive seen silicone and even pool putty used but those become a big fat pain if you ever want to pull the light. You can try that to see if the leak slows.

BTW, most pools have their return lines tied into each other. If this is the case with your pool the return lines would leak even if you only have one return plugged because they are T'ed somewhere between the filter and the return jets, however since your pool was built in '71 I wouldnt be surprised if the returns have 2 dedicated lines.

I highly recommend pressure testing the lines.


*this might not be so easy if you dont like cold water

 

[TomAtlanta]

An *easy* fix for the light is to take it out of the niche, see where the wire goes into the niche, then take some butyl tape and stuff it in the hole and around the wire to seal any leak in the conduit.

Can you do that with the water still over the light, or do you have to drain the water to below the light?

BTW, most pools have their return lines tied into each other. If this is the case with your pool the return lines would leak even if you only have one return plugged because they are T'ed somewhere between the filter and the return jets,

One return is plugged, and the water has leaked to a foot below the other return.

I highly recommend pressure testing the lines.

How hard would that be to do myself, and how much would I pay someone else to do it?

 

[TomAtlanta]

I know now where the leak is. I am going to put the cover over the pool for the winter and fix it in the spring. The pool has gotten green with algae. Would it be a good idea to put in a triple dose of shock, or to pour in a bottle of bleach or both, to kill the algae now, or should I just wait and deal with it in the spring?

 

[duraleigh]

Cover it and leave it 'til spring. a dose of bleach is not gonna' get rid of algae. You will need to shock your pool in the Spring. Read exactly how in Pool School and follow those directions carefully

 

[TomAtlanta]

Thanks for the info duraleigh

 

[HofstraJet]

Well, don't leave us in suspense.....where is the leak?

 

[waste]

Yeah Tom - where's the leak?

You never know how one of us can help you fix it

 

[TomAtlanta]

Sorry I left everyone hanging last fall. I forgot all about this topic as I got into pool chemistry.

It turned out that I did not really know where the leak was when I wrote that last fall. About a month ago after I uncovered the pool I got some high tech leak detector guys to come figure it out. They had a little camera that they could put inside the pipes, and some sound detector that they went over the ground with. They also did standard pressure tests. One guy wore a wet suit and got in the pool and did stuff with dye. It turned out there were two leaks, one around the light, which he fixed underwater with some underwater putty, and another leak in a pipe that you could hook to an automatic vacuum. That pipe was not used and not connected to the pump, but it was open at the pool and there was a leak in it. They just plugged that up. After those two things, the leak went away. They charged $350, which is their standard charge for a visit. Is that high, low, or about average?

 

[TomAtlanta]

The thing that brought me back to this topic is that now I think it might be leaking again, but it might also just be evaporation as the sun has gotten brighter and the days hotter. I am going to do the bucket test which people here have told me about. Does the size, shape, color or material of the bucket make a difference. It seems that all these things could effect evaporation rate, but maybe not enough to matter. I have a big clear plastic Coke cup that I have considered using, or a blue plastic bucket with slightly sloped sides, or I can just go out and buy what you tell me is best.

 

[Bama Rambler]

It really doesn't matter what the bucket is as long as it has sorta vertical sides (you woudn't want to use a flat dish). The color doesn't matter enough make a difference you can tell.

Most people just use an old 5-gallon bucket they have around.

 

[TomAtlanta]

Thanks for the info. It is hard to get the water lined up perfectly between the bucket and the pool, but I guess if there is a big difference it will be obvious in a few days. How much evaporation is normal in a pool in the summer?

 

[Bama Rambler]

You don't have to worry about getting the levels to match, just measure the levels carefully in each and then the next day measure them again. It's a difference in the amount lost that counts.

 

[Buford]

You tube has this: http://www.youtube.com/watch?v=U36G-LVproY which might be helpful.