3 week SLAM failure - phosphates

poolshrinker

Well-known member
Jun 4, 2016
70
Portland OR metro
Pool was fine all summer. I stay on top of the chemistry.

late August it started looking green. I SLAM’d, keeping chlorine at 14-16 per chart. I kept it there for 3 weeks. I brushed, but there’s really not much algae ‘sticking’ to the walls, a little in a crease on the floor, but mostly it’s just the powdery/floating stuff. I backwashed the pool twice during this time but pressure never bumped up more than 35%. I can’t think of where a hidden source of algae would be because it’s an AGP.

After 3 weeks, there is still algae forming in the pool and while the water got much clearer, it is not to its usual standards. In addition, I’m having trouble with my pump/motor so we called the pool company out to help with the second problem. Today while I was at work the pool guy told my wife our motor was starting to fail (there is no capacitor in this model) but there shouldn’t be a problem with our filter or sand needing deep cleaning because they’re relatively new. He’s going to get a new motor.

However he also ‘diagnosed’ very high phosphates, and said that may be part of why we’re not successfully SLAM’ing. He added some PhosFight. I don’t blame my wife because she doesn’t know these things, but the Pool School book says phosphates are irrelevant. That said, my wife found that very high phosphates can come from bird droppings, and this is the second summer in a row we’ve needed to SLAM, and both cases occurred about 2-3 weeks after coming back from a 2 week summer vacation during which time the murder of crows on our 2 acre property appeared to use our pool as a bird bath. We vacuum and so forth but it’s entirely possible that we aren’t successfully getting out all the stuff we need to.

Now we’re toward the end of the season I’m also running out of bleach and no local stores have any. So I’m probably going to have to close the pool a couple weeks no matter what and try to sort this out in the spring.

Any ideas what’s going on?
 

cowboycasey

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When you go on vacation the FC drops below the min level and algae starts growing..

SLAM: Are you checking FC and adding chlorine every 2 hours during the SLAM? The more you keep FC at SLAM level the faster it goes.. :)
 
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poolshrinker

Well-known member
Jun 4, 2016
70
Portland OR metro
When you go on vacation the FC drops below the min level and algae starts growing..

SLAM: Are you checking FC and adding chlorine every 2 hours during the SLAM? The more you keep FC at SLAM level the faster it goes.. :)
When I leave I take the chlorine up to 12. 1 week later a friend dumps in another gallon of chlorine. When I return home after I’m gone the chlorine is 4. It’s been very consistent.

During the SLAM I take it up to 16 and then check/add chlorine twice a day. It never drops below 14, I keep the cover on the whole time so sun isn’t adding much to the breakdown.
 

Bperry

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Aug 20, 2020
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When I leave I take the chlorine up to 12. 1 week later a friend dumps in another gallon of chlorine. When I return home after I’m gone the chlorine is 4. It’s been very consistent.

During the SLAM I take it up to 16 and then check/add chlorine twice a day. It never drops below 14, I keep the cover on the whole time so sun isn’t adding much to the breakdown.
You’d have to post some test results to get any better advice.
 
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Leebo

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Once a user has algae in their water the odds they also have high phosphates are very high. Algae contains phosphates in the walls of the cells so once the algae is killed off the phosphates are returned to the water. Adding the phosphate remover to the water did "remove" some of the phosphates that were in the water, but as soon as the algae is killed off the phosphates will only be returned. The proper way to remove phosphates when dealing with algae is to completely clear the pool THEN remove the phosphates.

I keep the cover on the whole time so sun isn’t adding much to the breakdown.
You need to remove the cover some during a SLAM as the sun will help break things down. When was the last time you opened the cover up some??
 

poolshrinker

Well-known member
Jun 4, 2016
70
Portland OR metro
Once a user has algae in their water the odds they also have high phosphates are very high. Algae contains phosphates in the walls of the cells so once the algae is killed off the phosphates are returned to the water. Adding the phosphate remover to the water did "remove" some of the phosphates that were in the water, but as soon as the algae is killed off the phosphates will only be returned. The proper way to remove phosphates when dealing with algae is to completely clear the pool THEN remove the phosphates.


You need to remove the cover some during a SLAM as the sun will help break things down. When was the last time you opened the cover up some??
sorry, unclear - we leave the solar cover on but it’s not the winter cover - do i need to remove the solar cover?
 

cowboycasey

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At least a couple hours a day to allow the CC's to burn off :)
 
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