Multiple Problems - suction side leak - filter/sand issues

CincyDools

Active member
May 18, 2017
44
Cincinnati, Ohio
Sorry for the long post but these problems have me pulling my hair out. Trying to provide as much info as possible to avoid clarifying questions.

BACKGROUND
Last year I had issues using my vacuum head on my Shallow Skimmer. When I tried to shut my main drain and/or Deep Skimmer valves to get god suction so I could vacuum. Finally found the right combination of closing valves to get decent but not great suction to my vacuum head. Not great but decided to live with it and occasionally used the deep end skimmer to vacuum. Towards the end of last season, I started losing about an inch of water over night. I attributed this to increased evaporation due to the fact that we added a heater at the beginning of last season without putting a solar cover on over night.

Fast forward to this year. The shallow end skimmer issue seemed to worsen. And I was starting to lose 1-2 inches of water over night depending on whether I left the filter running over night. I had driven T-posts in the ground near the pool deck to put up a fence around my garden -thought for sure I must have gotten into one of the return lines. So I decided it was time to bring in a Leak Detection Company. Luckily they found that all of the returns held pressure. The low end skimmer had a very bad leak and they located it. They said it was bad enough that it would explain the bubbles in the basket and additional loss of water. The Deep Skimmer had a very small leak that they had trouble locating and suggested that it was small enough to not worry about for now. The main drain plumbing held pressure. I made an appointment 3 weeks out for them to come repair the shallow end skimmer plumbing. I plugged the shallow skimmer at the skimmer and turned off the valve so that I could limp along for 3 weeks with the deep end skimmer. Unfortunately, I did not fire up the pump before the technician left. I thought I would give the glue on the returns plumbing a little extra time to set before firing things up. Ever since then, I have had a suction side leak (bubbles in the pump basket) that I cannot find. I am able to run the pump with a moderate amount of bubbles and am getting 20 lbs of pressure.

PROBLEM 1 - suction side leak
The leak detection company said they will address the problem when they come back out in three weeks but I am trying to locate the issue before then since the problem must be above ground (somewhere between where the suction lines some out of the ground and where the enter the pump). I have tried all the usual methods for finding suction side leaks except for the smoke method because it has been too windy. I have tried dowsing all joints, unions, plugs and pump basket with running water. Tried soapy water and soap suds. Tried shaving cream and Saran wrap. No luck with any of these methods. I get about the same amount of bubble in the basket whether I open the deep skimmer valve or the main drain valve or turn both on at the same time. So this makes me think the leak must be between where the three suction lines (each with their own valve) T together and go to the pump. After the T there are two glue joints (one on either side of a union, and a glue joint for the threaded coupler that goes into the pump. I cannot find a leak in any of those places even after reseating the union and threaded connection. I also replaced o-rings and re-taped the pump drain plugs. I also added lube to all of the rubber seal points including the basket lid.

Any ideas what else to try?

PROBLEM 2 - Backflow of water into the pool
Since the leak detection technician left, when I shut off the pump, I get a huge rush of water coming back into the pool from the main drain and skimmer, the pump basket empties and loses prime. After this happens it takes a lot of time and effort to get the pump primed and running again. From reading other threads, it sounds like this is due to a build up of air in the filter from the suction side leak. I do not have a air relief valve to let the air escape. I saw somewhere that you could loosen your pressure gauge to let air out but that has not worked - only water comes out. So how can I release air with the pump running if I don't have a relief valve?

It has been quite a while since my sand has been replaced. The sand level seems to be a little below half full. The sand also seemed to feel a little mushy (not gritty) but I don't know what it is supposed to feel like. Could this sand level and condition be contributing to my backflow issue?

ADDITIONAL INFO - possible spider gasket issue

My pool store said they thought the spider gasket, union gaskets and basket gasket look okay. I get the same amount of bubbles in the basket whether the multi-port valve is set to Filter or Recirculate. When on Recirculate, I get a small amount of water coming out of the Waste port but not when on Filter. When I turn off the pump while on Recirculate the backflow is not quite as bad but air blows out of the waste port (I think this might be normal?).


Any ideas you have while I am waiting for my leak detection guy to come back out would be greatly appreciated. Also trying to figure out if I should try to get my regular pool guy come out to check my filter and sand before them. Really tough for me to figure out since there appears to be multiple issues at the same time.

THANKS IN ADVANCE FOR YOUR HELP!
 
Last edited:

Pool_Medic

In The Industry
Apr 1, 2018
1,533
Bangor Maine
Firstly, when two skimmers are on one suction line its normal to use a gizmo to plug one, then you shut off main drain and pull the water from the skimmer that isn’t plugged. This gives you great suction when you manually vacuum.

PROBLEM 1 - suction side leak
The leak detection company said they will address the problem when they come back out in three weeks but I am trying to locate the issue before then since the problem must be above ground (somewhere between where the suction lines some out of the ground and where the enter the pump). I have tried all the usual methods for finding suction side leaks except for the smoke method because it has been too windy. I have tried dowsing all joints, unions, plugs and pump basket with running water. Tried soapy water and soap suds. Tried shaving cream and Saran wrap. No luck with any of these methods. I get about the same amount of bubble in the basket whether I open the deep skimmer valve or the main drain valve or turn both on at the same time. So this makes me think the leak must be between where the three suction lines (each with their own valve) T together and go to the pump. After the T there are two glue joints (one on either side of a union, and a glue joint for the threaded coupler that goes into the pump. I cannot find a leak in any of those places even after reseating the union and threaded connection. I also replaced o-rings and re-taped the pump drain plugs. I also added lube to all of the rubber seal points including the basket lid.

Bubbles signify a suction leak, use new o rings and carefully check the pump lid. How is your pool plumbed, flex joints can become loose, rigid or flex? That threaded coupler could be an issue as it might be loose and allowing air in.

PROBLEM 2 - Backflow of water into the pool
Since the leak detection technician left, when I shut off the pump, I get a huge rush of water coming back into the pool from the main drain and skimmer, the pump basket empties and loses prime. After this happens it takes a lot of time and effort to get the pump primed and running again. From reading other threads, it sounds like this is due to a build up of air in the filter from the suction side leak. I do not have a air relief valve to let the air escape. I saw somewhere that you could loosen your pressure gauge to let air out but that has not worked - only water comes out. So how can I release air with the pump running if I don't have a relied valve?

It has been quite a while since my sand has been replaced. The sand level seems to be a little below half full. The sand also seemed to feel a little mushy (not gritty) but I don't know what it is supposed to feel like. Could this sand level and condition be contributing to my backflow issue?

Backflow is a pressure side leak normally. Recheck all connections from pump to returns. When wet the sand does feel mushy but you need to being the sand level up to where the filter body starts to narrow.
 
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