Leak level identified, can I run the pump with pool half full?

[DerekP]

Hey everyone,

Blowing out my lines last fall apparently caused a pipe joint running to my bottom drain to spring a small leak. The water level continued to go down until it stabilized months ago. I have a 37,000 Gal vinyl inground pool. The shallow end has about 3" of water in it and deep end is about 4.5' deep and 45 degrees. The current level is about 3.5-4' too low. The plan is to plug the bottom drain and occasionally circulate the deep end with my Vac hose once the water level is restored. I have valves for the Vac, Skimmer and bottom drain. I would love to start running the pump now to circulate the warm water in the shallow end to help bring the water temp up so I can dive down and take the bottom drain cover off and plug the bottom drain pipe and then begin filling the pool back up. The current water level has remained constant for months, so I know the leak is somewhere underground at that level. The water level is below anything that cuts into the vinyl, stairs, returns, lights etc... leaving the only reasonable answer, there's a leak in the bottom drain plumbing at that level. The vinyl lining is 5 years old if that is pertinent. The owner replaced the year I bought the house. His bad, my win.

The question is, will it be safe to use my vac line with the hose in the deep end to push water through the returns with low water levels. I wonder if the pump will prime? The returns are a little less than 3' above the current water level and would splash outward into the pool. The skimmer valve would obviously remained closed rendering skimmers out of use. The result I'm trying to achieve is to a) balance and warm the water, b) plug the bottom drain pipe with a cap once the water is warm enough for me to take it, c) begin filling up the pool.

Is this advisable or are there issues I'm not seeing?
Thanks
Derek

 

[Newdude]

The shallow end has about 3" of water in it and deep end is about 4.5' deep and 45 degrees. The current level is about 3.5-4' too low.

Its more likely its the liner IMO. The bottom of the stairs gaskets about that high and would be my first guess. Guess #2 would be a bad seam, which is suspiciously also at that level all around.

What did you use to blow the lines ? If using a compressor, how many PSI ? 2 inch PVC should be good to 280 PSI, although every joint in the land isn't perfectly glued.

 

[wireform]

If it was a cracked line more water should be gone. As @Newdude ^^^^ said. If you're already going down there don't condem the line until you pressure test it otherwise you plug and refill only to lose the water again via a liner leak.

 

[DerekP]

It's 2" line in, 1.5" return out. I had my compressor in 50 PSI range. I know the pipes should handle that PSI. But... I blew the lines out late, in January before a cold snap. I did not cover the pool and over the next few days after I blew out the lines my wife said the water line is getting lower. We watched the level go down over a couple months until it's current stabilized level. It seems oddly suspicious to me that a liner would all of sudden spring a leak right after or when I below the lines out. There are a couple areas in the shallow end where there potentially could be a seam leak they are above or near water level. The rest of the pool has the seam still a couple inches below water level. Also attached a pic of the ladder. It is high and dry.

Rather than put a pvc cap on the pipe in the bottom drain, I'm hearing that I should somehow pressure test it before condemning the line? The problem is, I still have to be able to withstand the temp to get down there. I don't have a dry suit or wet suit. Would it be safe to run pump to get some circulation going in pool and to also get some chems going to manage it?

 

[wireform]

You need minimum 12" of water in your shallow at any given time or else you risk the liner altogether.
You may try to use the MD as the suction side intake keeping the skimmer valve closed and just let it return into the pool via the return jets to warm the water.

 

[DerekP]

What happens to the line with low water levels? Will it just not stretch back into place?

 

[wireform]

What happens to the line with low water levels? Will it just not stretch back into place?

Can you rephrase the question please, don't understand.

 

[Newdude]

*liner. Not 'line'


And yes. It may not stretch back into place, or to the same place. Wrinkles are common if it shifts.

 

[wireform]

Just thought about something. If the plumbing passes the test then the problem spot will be right at the water line where it's at now so if your in the warm water look very well. Fast forward: Say you've found the leak and patched, when you refill with the heater going the warm water may make the liner push back into the corners.

 

[DerekP]

Thanks guys - sorry for the confusion with "line" vs "Liner". I have some wrinkles in two corners, and I've been able to begin to work them back into the corner. Pretty sure I can get this done as the warm weather approaches.

 

[Newdude]

Toilet plungers (preferably new. Lol) work surprisingly well to shift the floor around.