Nasty algae - pool open

angfiggy

Well-known member
Sep 2, 2017
76
NE
Pool Size
22000
Surface
Vinyl
Chlorine
Liquid Chlorine
This is my sixth pool opening and instead of getting better at opening, I really appear to be getting worse. Maybe I am too impatient with the process but the stubborn persisting algae is really starting to irritate me.

Upon opening the pool, I tested for ph first, and it appeared good. Cya was at around 20, so I started slamming with liquid chlorine, vacuuming with the hose vacuum and brushing/raking.

Slam goes really really well until day 3 when it appears to stall. This year, I hit it even harder with chlorine. My levels were around 25+ FC and maintained those for 7 days. In day 7, I’m frustrated and impatient. The pool is changing slowly to blue but I can see dark outlines and my water isn’t clear. So I brush, brush, rake, rake, vacuum, vacuum. I am still hitting spots where I’m pulling nasty stringy green algae. Backwash shows that I’m getting there, the water is changing to less brown/green….and then I need to leave for a week. I raised cya a bit to 30-35ish, left my mother in law with strict instructions on how much chlorine and will cross my fingers.l that it holds until I get back or by some miracle gets a little more clear.

So, again, frustrated. Is there something I can use to make the chlorine sit on the algae in the trouble spots to kill it off. Or maybe I simply need to open earlier so if it takes longer to clear, it’s still to cold to swim. I have been pouing the liquid chlorine and immediately brushing. The algae seems to come right back and it’s in the same spots. Grrrrrr…. Last year it took 2 weeks to clear at slam.
 

AK-

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May 11, 2021
963
Northwestern NJ
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Opening earlier is definitely the way to go. Close at SLAM level when water temp is below 60F and open before the water goes above 60F. The colder the water the better. You could even do a partial opening when temps go above freezing removing just enough cover to have access to you skimmer and to test the water and remove the cover at later date.

Both chlorine breakdown and algae growth are slower in cool temperatures. By opening earlier you might still have enough chlorine to prevent an algae bloom altogether. If the opening algae is a consistent problem you could add some Polyquat 60 at closing to help out.

Troubling spots are usually due to either poor circulation (sometimes it is something getting in the way ) or poor brushing (the biofilm will protect the algae underneath from chlorine). Try dosing a little of the chlorine on those trouble spots and do extra brushing there.

Have you tested you water for iron to make sure the green/brown is not a side effect of the SLAM?
 

angfiggy

Well-known member
Sep 2, 2017
76
NE
Pool Size
22000
Surface
Vinyl
Chlorine
Liquid Chlorine
Thank you. Super helpful. Opening algae is a consistent issue. I close it in September and it’s nice and blue. Open it in May and it’s a dark green already.

No. I haven’t tested for iron. Can you expand more on that? We have well water, too.
 
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AK-

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May 11, 2021
963
Northwestern NJ
Pool Size
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Vinyl
Chlorine
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SWG Type
CircuPool RJ-30
No. I haven’t tested for iron. Can you expand more on that? We have well water, too.
One of the few things that pool stores tests are really useful is to detect metals. Sure, you could buy test kits for those, but generally speaking all you want to know if you have or not metals and what metals, while the actual concentration does matter that much.

Free iron is oxidized by chlorine. The first "stage" will tint the water green, but not make it cloudy. Enough iron and chlorine and the water will turn brown.
There are steps that can be taken to mitigate that, but in order to mitigate it you first need to know if metals are at play or not.
 

AK-

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May 11, 2021
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Northwestern NJ
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Alright. Geez. I really don't like going to the pool store here, but I will take it in. They are awful.
There are test kits for metals... they are expensive and it is very hard to justify the expense....

In terms of metals, you want to know if you have or not... if the pool store result has the wrong amount that is not very relevant.
 

angfiggy

Well-known member
Sep 2, 2017
76
NE
Pool Size
22000
Surface
Vinyl
Chlorine
Liquid Chlorine
Well, I will see about their readings. I just tested my water, so will see how accurate their results are. I was mainly talking about their attitude and their customer service. :D They would not support my pool pump; they are the only Pentair dealer within a 200 mile radius and I was left to fix it myself. Pentair did let me fix it, under warranty, which was amazing, but I don't get excited about walking back into that store. They also tried to tell me that menard's pool shock is not really chlorine and I am stupid for not buying their products, which are superior.

Let's see if they have an iron test....
 
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V___25

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May 30, 2020
565
Central PA
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When you close, is your water still above 60*? We close late October or whenever it falls below 60. This year I did a “soft open” and pulled the cover in April because I had bright green algae in the skimmer box. I didn’t turn on the pump or dewinterize the plumbing due to freezing overnight temps but I added chlorine by stirring with a brush and running the robot.

I would try closing later and opening early.
 

angfiggy

Well-known member
Sep 2, 2017
76
NE
Pool Size
22000
Surface
Vinyl
Chlorine
Liquid Chlorine
No iron in the pool.

No. The water is usually below 60 degrees when I close. The weather fluctuates here though and we had a really mild winter. I'm sure I was building algae throughout Nov/Dec this year when temps kept swinging back in the 70s. But, I have to close in Oct when temps start swinging towards freezing at night. So, perhaps Polyquat upon close to help and then partial open in late March/early April with winter cover partially off a corner so I can start dumping chlorine and brushing. Maybe try a soft open like you did in April. I can try that.
 
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