Slow leak from somewhere - advice please?

[kim]

Hi
I bought a house 6 months ago that has a pool and a spa.
For the last few weeks, I have been struggling to determine the cause of a leak in the pool.
I have been searching help sites for ages trying to find out the best thing to do first.

1. I checked the filter system and all the piping there.
There is a very small drip coming out of the pipe that goes from the pump to the filter. At the point where it feeds into the filter gasket - I notice about 1 drop every 10 mins forming. Have resealed it using teflon tape (previous owners had gunked it up with some other stuff which apparently should not be used).
I also noticed wet around the part where the same pipe is connected to the pump. There was no water around this on the floor - so I assume this wasn't a big deal. Have tightened up and teflon taped the pipe join.

2. I have done the bucket test. Filter off and I lost about 2 mm of water in the pool.
I haven't done an accurate one with the filter on yet.

3. I have 4 returns - I notice I get just water coming out what I assume is the first in the line, and then very small bubbles coming out of the second, not much coming out of the 3rd (can't recall if I checked if this was actually returning water or not) and small bubbles coming out of the 4th (which I assume is the last in line - but I don't have the plans for the pool yet - am still waiting on the previous owner for them).

4. I have switched off the input from the skimmers as the water has dropped to far low for them. This is in a bid to determine if there was a leak at the skimmer boxes. The water fell below the level though.

5. I have used food dye while the water was dead still around any opening to the pool where 2 different media meet. This includes returns, skimmers, lights, solar drain, solar returns. The dye sits in the water and does not get sucked anywhere.

6. I have had the filter gasket taken apart and put back together (before I noticed the water loss).

7. Since I noticed the water loss, I have had the backwash fitting checked to ensure no water being lost down that pipe.

I didn't move in to the house till about 6 weeks ago at which point I noticed a crack in the paving in a diagonal line between the pool and spa (not all the way). No wet spots, just a crack - and initially I put it down to a bad paving job and the drought. I am concerned though that there might be a leak here possibly caused by the movement in the ground.

The other thing in my thinking is that it could be an issue with the main drain - I reckon its got all sorts of debris in it - although it is too cold here to dive down and find out.

Do you think Now is the time to call someone in?? Or is there anything else I should check first??

Thanks for any advice - I think I have tried everything here unless someone can suggest something different??

[ChuckGeo]

I'd recommend a full set of water loss measurements before you call in a professional. Specifically, you want to determine the loss when the pool is on and off, as well as the loss from the spa when it is on and off. The best way to get these measurements is to valve off the spa on the first day, mark the pool and spa levels, run the pump for 24 hours and measure the "on" loss from the pool and the "off" loss from the spa. On the second day, set the valves to spa operating position, mark the levels in the pool & spa, run the pump for 24 hours then measure the "off" reading from the pool and the "on" loss from the spa. With this information in hand a leak professional should be able to diagnose the problem fairly quickly, or post the results here and I'll interpret them for you. By the way, it would be helpful to have your results in inches as well as centimeters, as a lot of us don't work in cm.

[kim]

Thanks Chuck

I will do another test this week, and of course provide you the measurements in inches too!

Kim

[kim]

Hi

I have an update:

The water stopped dropping when it got to a little way (no more than about 1/2 inch) below the skimmers.
I still did the test with the pump input from main drain in pool only (not spa) and with everything switched off.
No water loss over 24 hours for either.

One thing I noticed was when I ran the pump I could still hear some gurgling from the skimmers even though they are switched off. I took the baskets out and there was a small amount of water (probably going to about 1/2 way up the pipe at the bottom) same level on both skimmers.

Now due to the gurgling, does that mean the shut-off valves (which have a lever, not a 'wheel' like the gate valves) don't seal close properly? Or does it mean that there is a leak in the pipe from the skimmers to the pump? Can I test this by switching the pump off and filling the skimmers to the top of the basket and leave for 24 hours (is this a valid test)?

Having taken a look at both skimmers, I can see a couple of tiny cracks between them and the concrete. I bought some 2 part pool putty so will mix and apply that. I have checked the plastic and I can't find any cracks or damage. Would those tiny cracks really cause that amount of leaking? (6 inches over 4 weeks)

What should my next steps be?
Should I still test the spa suction and return is working ok?

I would rather try and get everything in one go rather than keep filling up the pool.

[ChuckGeo]

The first thing I'd check would be the skimmer throats, where the plastic skimmer butts against the pool. That joint is the #1 leak spot in gunite pools, you should be able to see a crack or gap in the joint.
The gurgling at the skimmers probably means that the skimmer valve is leaking a little when it's closed, doesn't really mean anything. However, it would be a good idea to close the skimmer valve, turn off the pump and fill the skimmers with water (the pool water level must be below the front skimmer opening), check to see if they loose water after 24 hours. If they do, you might need to pressure test the skimmer line to test for leak.
Keep in mindthat you're looking for a fairly small leak - 6" in 4 weeks translates to less than 1/4" per day.
Good luck.

[kim]

Thanks Chuck.

There was a small (paper edge thickness) gap between where the skimmer box met the pool.
Using a flat knife I could actually insert this all the way along between the bottom of the skimmer box and the wall.

I mixed up my Emerkit and applied the putty this afternoon and did the other skimmer box for good measure. I just have to wait for it to harden up now.

I've also filled the skimmer baskets to the top with water - I will check on those tomorrow to see if there is any drop.

I am going to do a double check of the wall of the pool at the top just to be 100% sure I haven't missed a crack or anything. The reason for this, is that I am concerned that it has dropped 1/2 - 1 inch below the point where the skimmer meets the concrete - but if I surmise that this is because of water movement when the pool is running - would I be right?

If I find nothing else - then I am all set to go for topping up. The ground movement is still worrying me and I am concerned I may still have a damaged return line - but I guess the only way I will know that is to pressure test the returns?

[kimj]

Chuck

So far, so good.

Pool has not dropped since the fix, filter has been running from both skimmers and main drain.

I had to backwash the filter as the water in the returns was looking a bit cloudy initially.

I also took the water to be tested - Chlorine was a bit high, but all other levels were fine (considering I haven't run the filter much over the past couple of weeks its a nice surprise)

Hopefully I have saved myself a few hundred dollars - I sincerely appreciate your input though as you gave me the confidence to just keep at it a little bit longer.

Thanks
Kim

[kimj]

Hello

Well I thought I had it - water stayed at a stable level for a day!

Now its dropping same rate as before - 1/4 inch per day - with or without pump on.

I could re-do the skimmers - any other suggestions?

Thanks in advance
Kim