Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 3 of 3

Thread: Uping

  1. Back To Top    #1

    Join Date
    Jun 2011
    Folsom, California


    Executive summary: Increasing bubbles in return as flow rate decreases below 35GPM while solar panels are active.

    Over the past 2-3 weeks, I've noticed increasing bubbles in the return while water is routed through my solar panels. To eliminate one possibility, I turned off my SWG which typically made some small bubbles and it had no impact. I suspect there may be a leak somewhere along the solar panel lines on the roof of my 2-story house, but would expect to see water dripping out too which has not yet been seen. The sudden increase in bubbles is so great that my Polaris crawler floats to the top of the pool and becomes useless. To get the bottom of my pool cleaned up quicker, I turned off my solar panels and increased my flow rate from 28GPM to 38GPM. Once mostly clean, I went ahead and turned on the solar panels only to find everything appearing to run normally again without any bubbles! Given my engineering background, I wanted to determine what flow rate was needed to avoid bubbles. It turned out that flows at or above 36GPM were bubble-free while bubbles clearly appeared at 35GPM and increased as the flow rate decreases. I would have actually expected the opposite prior to this experiment.

    Does anyone have suggestions as to what the problem may be or how to debug further?
    13,500 gallon in-ground 30'x15' kidney shaped plaster pool, Swimpure Plus 40K SWG, Pentair variable speed pump, Polaris crawler, solar panels

  2. Back To Top    #2

    Join Date
    Jun 2012
    western NY

    Re: Uping

    An interesting experiment would be to have a pressure gage and vacuum gage near or at the top of the system to see what is going on up there. Ideally it would be nice to be able to measure either one as the water turns back down to see what is happening. I am willing to bet as the water nears the top and starts back down the pressure at the lower flow rates actually goes negative enough to pull the entrained air out of the water. We combat this problem in hydronic heating systems two ways, one is by increasing the system pressure and the second is to install air scoops. Since this is not a closed/sealed system, air is constantly being added to the water so I suspect that increasing the flow rate overcomes the tendency for the water to be able to give up the entrained air.
    Unknown make 18' above ground (bought used in 1999) Sparco sand filter. Hayward 100,000 BTu heater. 2 speed pump

  3. Back To Top    #3
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    SW Indiana

    Re: Uping

    I'd be looking at your vacuum breaker. It may not be sealing at lower flow rates.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts