Recommissioning a dirty pool

sirenian

Member
Sep 27, 2021
6
Boston, MA
I'm cleaning up a 30,000 gallon outdoor pool in MA that sat open to leaves and detritus for around two years. So far, we've have:

  • Replaced the seized pump motor
  • Replaced the the pump seals
  • Replaced the cracked valve innards
  • Replaced leaky glued hard pipe between the pump and filter with new hard pipe and union fittings.
  • Scooped and vacuumed out a thick layer of leaf and algae muck
  • Brushed regularly
  • Taken out the railings and ladders to be scrubbed separately
  • Brought the chemistry to:
    • Alkalinity: 50ppm
    • pH: 7.2
    • Calcium: 275ppm (probably will level out above 300ppm after my final addition today.)
    • CYA: 50ppm
    • Chlorine: shocking 1x/day to 20ppm with cal hypo, losing about 5ppm per day now. No CC registering at the moment. We're about to use up our 50lb bucket.
Our assumption, up until now, was that the pool was too dirty to start a real SLAM.

Now, the pool water is blue, but quite hazy. We'll switch to bleach one the cal hypo runs out, and start a SLAM. I'm hoping that the haze will dissipate both from clearing out any algae and stopping cal hypo use.

Is there anything else we should be doing?
 
I'm cleaning up a 30,000 gallon outdoor pool in MA that sat open to leaves and detritus for around two years. So far, we've have:

  • Replaced the seized pump motor
  • Replaced the the pump seals
  • Replaced the cracked valve innards
  • Replaced leaky glued hard pipe between the pump and filter with new hard pipe and union fittings.
  • Scooped and vacuumed out a thick layer of leaf and algae muck
  • Brushed regularly
  • Taken out the railings and ladders to be scrubbed separately
  • Brought the chemistry to:
    • Alkalinity: 50ppm
    • pH: 7.2
    • Calcium: 275ppm (probably will level out above 300ppm after my final addition today.)
    • CYA: 50ppm
    • Chlorine: shocking 1x/day to 20ppm with cal hypo, losing about 5ppm per day now. No CC registering at the moment. We're about to use up our 50lb bucket.
Our assumption, up until now, was that the pool was too dirty to start a real SLAM.

Now, the pool water is blue, but quite hazy. We'll switch to bleach one the cal hypo runs out, and start a SLAM. I'm hoping that the haze will dissipate both from clearing out any algae and stopping cal hypo use.

Is there anything else we should be doing?
What type of filter do you have? Are you monitoring the increase in filter pressure? You should backwash when pressure is 25% above the starting (clean) filter pressure. Have you backwashed it?
You should be testing and adding chlorine every 4-5 hrs to maintain it at 20ppm FC. That will help clear.
 
What type of filter do you have? Are you monitoring the increase in filter pressure? You should backwash when pressure is 25% above the starting (clean) filter pressure. Have you backwashed it?
You should be testing and adding chlorine every 4-5 hrs to maintain it at 20ppm FC. That will help clear.
It's a sand filter, and we've been clogging it like mad clearing out the algae and sediment. We've probably backwashed 30 times. The pool has finally cleared to the point where we only need to backwash every 2-3 days.

And yes, we'll be starting a SLAM shortly. Until now, with the amount of solids we were pulling out of the water, it seemed wasteful to try to maintain SLAM levels.