algae that doesn't go away no matter how high the chlorine

Chaya

Bronze Supporter
Jul 28, 2019
72
Lakewood, New Jersey
I'm completely exhausted from battling algae that doesn't seem to go away. normally, if during the season i see some algae, i brush, vacuum and shock and leave the filter running overnight. typically the next morning i wake up to dead algae in grey clusters on the floor of the pool. i then vacuum the pool and i'm done with it.

my pool is normally closed by now but following the advice i saw here, i decided to leave the pool open until the water fell below 60 degrees. i figured it would not be too much extra work and worth the time i would save next spring. the opposite occurred. about a month ago i noticed yellow streaking on the bottom of the pool floor. i brushed and seemed to have major algae. i shocked, ran the pump, vacuumed etc. every time i go through a cycle of brush, vacuum, shock the pool looks great for about 2 days. then i brush again and see yellow puff up i the water. it occurred to me after a few cycles of this that i am never seeing the dead algae drop to the floor. i seem not to be killing it - it just seems that i brush it off the surfaces, clouds into the water and then falls back again within the next day or two. WHY? i am talking about chlorine levels in the 30ppm range!!

i want to be done with maintaining the pool! i have been spending more in electric and chlorine than if i had closed the pool a month ago and been done with it. I dont want to be testing water in october! this was supposed to be easy... and we have not swam since end of august...

as of this morning my FC was 26, CC 0, alkalinity 60 (i know a little low), CYA 60-70, PH 7

what is going on? any advice would be appreciated...
 
yes, i've read and read it 100 times. i had the chlorine up in the 30s and vacuumed and brushed. the pool cleared and i didnt lose any chlorine overnight.
but i didnt test 3-4 times a day.... i've lost hope, i dont have hours to spend each day by the pool!

ok, i'm going to try one more round, no shortcuts and after that i quit.
 
Getting the algae to DIE isn't a one time dose..... that's what it sounds like you've been doing. Its a matter of *maintaining* that SLAM level of chlorine until there is no more algae reproducing in your water. You could have hidden algae behind lights, under ladders, in the skimmer....all sorts of places that aren't getting exposed to all that chlorine on that one pass.

Don't forget to brush daily while killing it.... that's disrupts the biofilm protecting the algae and allows the chlorine to get in there good.

Maddie :flower:
 

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Chaya, I am going through the exact thing as you are next door in Brick NJ. Got ready to close the pool a few weeks ago, noticed some (what I think) mustard algae. Started the SLAM process on September 22, still doing it. My pool is crystal clear, my combined CL since I started has never been higher than 1.0 but the algae keeps coming back after a few days. I brush and vac to waste and backwash as well. It's frustrating as heck.
 
Getting the algae to DIE isn't a one time dose..... that's what it sounds like you've been doing. Its a matter of *maintaining* that SLAM level of chlorine until there is no more algae reproducing in your water. You could have hidden algae behind lights, under ladders, in the skimmer....all sorts of places that aren't getting exposed to all that chlorine on that one pass.

Don't forget to brush daily while killing it.... that's disrupts the biofilm protecting the algae and allows the chlorine to get in there good.

Maddie :flower:
why are you saying its not a "one time dose". if i should be maintaining chlorine levels of 28 for example, and i raise it to 40, for example, just so i don't have to be busy adjusting my chlorine 3 times a day, and it stay above the 28 mark for consecutive days, why won't that do the same trick?

regarding hidden algae, i have no lights and i removed my ladder so i would not have to worry about it.

and it seems strange, in spite of what everyone is saying, that i would need so much chlorine to kill a tiny bit of algae. when i open the pool i put in about 3 lbs of shock and maybe add another bag after a few days and the totally green pool clears to blue. here i have been putting in bag after bag of shock without killing this algae once and for all!
 
Chaya, I am going through the exact thing as you are next door in Brick NJ. Got ready to close the pool a few weeks ago, noticed some (what I think) mustard algae. Started the SLAM process on September 22, still doing it. My pool is crystal clear, my combined CL since I started has never been higher than 1.0 but the algae keeps coming back after a few days. I brush and vac to waste and backwash as well. It's frustrating as ****.
is it really mustard algae? i thought mine was for years... but just this season i started doubting it.
someone on this forum said that if its puffing up & clouding into the water when brushed its just regular algae.

all i know is that i had a crystal clean pool for years and years with no algae problems after initial opening right until the end of the season, never did anything "right" (before i even found this forum) . and now... it all the time.
 
As you have read the SLAM article "100 times" you know that are not following it correctly. You're blindly adding chlorine and not keeping at it consistently, it shouldn't be a surprise that things aren't going exactly as it should.

If you correctly follow the SLAM Process until you pass all criteria then the algae will go away. If you keep doing the same thing over and over again then you are bound to keep getting the same results.
 
Last edited:
You ask me --->
why are you saying its not a "one time dose".

Because this is the first thing you said -->
i brush, vacuum and shock and leave the filter running overnight. typically the next morning i wake up to dead algae in grey clusters on the floor of the pool. i then vacuum the pool and i'm done with it.

"Bags of shock" are NOT the normal treatment in the SLAM process. If those "bags of shock" are stabilized with CYA, you're raising the bar of how much FC you need to add to get the desired result.

Maddie :flower:
 
Hello! Please keep trying and don't give up.

Are you using liquid chlorine to SLAM your pool or bleach. If you're using bleach, please use the plain stuff (no splashless, scents, or polymers. No Clorox or cloromax - no additives). Do not use any other form of "shock" treatment.

Make sure you leave you pump running 24/7 while SLAMing your pool (proper circulation/filtration of the pool water is recommended). Again, do your best to maintain the proper SLAM "FC" level based on your current CYA FC/CYA. Continue vacuuming and brushing pool each day while in SLAM mood.

Since you have algae, chlorine may decrease rapidly as algae is being killed off, so test for FC every couple of hours (if you can or if you're at work...morning, lunch time, evening-as frequently as possible). Again, maintain the shock level by adding the correct amount of chlorine/bleach when necessary.

brush..brush..brush... while in SLAM mode.

I know this could be very frustrating, but please hang in there. Just follow the SLAM process rigorously and you'll be golden before you know it.
 
is it really mustard algae? i thought mine was for years... but just this season i started doubting it.
someone on this forum said that if its puffing up & clouding into the water when brushed its just regular algae.

all i know is that i had a crystal clean pool for years and years with no algae problems after initial opening right until the end of the season, never did anything "right" (before i even found this forum) . and now... it all the time.
So at the beginning of this season I got a new vinyl liner replacement. I hired the company who installed it to come once a week to clean and add chemicals (after 15 years of taking care of the pool myself, I decided to take it easy for a change). All was well until a few weeks ago. I suspected it was MA and the pool tech confirmed it. That being said, I'm not totally convinced that it is in fact mustard algae. It appears initially on the floor near the returns as nickel sizes spots, greenish-yellow in color. then it settles in larger areas on the rest of the floor but as a layer of silt that clouds up when brushed. It also is on the walls but it's harder to see it there. I see it when I brush the walls. It comes off easily with brushing. I believe the forums suggest that if it appears on the walls then it's not pollen, but IDK.

So I did the SLAM for about 2 weeks as I said in the earlier post. I use liquid chlorine 12.5% sodium hypochlorite bought from the pool store. (In the 2 weeks I used about 15 gallons of it.) Then I shocked at Mustard Algae level for 24 hours. I passed the OCLT during SLAM. The pool looks pristine clear, my free chlorine level is coming down now. I am closing the pool tomorrow. Hopefully I won't need to resume this battle next year.

Hang in there Chaya. I used to shock using powdered shock but I now use the liquid instead. It's much better in my opinion. You can get 5 gallon containers of it for about $20 at the Home Recreation store in Brick. They also have it in 1 gallon bottles by the case.

I also have a question for the experts here. Is it alright to use "sodium thiosulfate pentahydrate Na203s2 dechlorinator" to lower the chlorine level in the pool so I can properly balance the water for closing? Thanks for your expertise!
 
You ask me --->

Because this is the first thing you said -->

"Bags of shock" are NOT the normal treatment in the SLAM process. If those "bags of shock" are stabilized with CYA, you're raising the bar of how much FC you need to add to get the desired result.

Maddie :flower:
i use calcium hypochlorite - i dont think that contains stabilizer. I KNOW everyone recommends liquid chlorine but what am i missing? it sounds SOOO impractical.... Who can lug cases and cases of heavy chlorine from the pool store or other store? they are not available for purchase online as far as i know (for any reasonable price). but calcium hypochlorite comes straight to my door, in 2 days, for a good price from amazon. where do you buy your liquid chlorine from?
 
Hello! Please keep trying and don't give up.

Are you using liquid chlorine to SLAM your pool or bleach. If you're using bleach, please use the plain stuff (no splashless, scents, or polymers. No Clorox or cloromax - no additives). Do not use any other form of "shock" treatment.

Make sure you leave you pump running 24/7 while SLAMing your pool (proper circulation/filtration of the pool water is recommended). Again, do your best to maintain the proper SLAM "FC" level based on your current CYA FC/CYA. Continue vacuuming and brushing pool each day while in SLAM mood.

Since you have algae, chlorine may decrease rapidly as algae is being killed off, so test for FC every couple of hours (if you can or if you're at work...morning, lunch time, evening-as frequently as possible). Again, maintain the shock level by adding the correct amount of chlorine/bleach when necessary.

brush..brush..brush... while in SLAM mode.

I know this could be very frustrating, but please hang in there. Just follow the SLAM process rigorously and you'll be golden before you know it.
 
Hello! Please keep trying and don't give up.

Are you using liquid chlorine to SLAM your pool or bleach. If you're using bleach, please use the plain stuff (no splashless, scents, or polymers. No Clorox or cloromax - no additives). Do not use any other form of "shock" treatment.

Make sure you leave you pump running 24/7 while SLAMing your pool (proper circulation/filtration of the pool water is recommended). Again, do your best to maintain the proper SLAM "FC" level based on your current CYA FC/CYA. Continue vacuuming and brushing pool each day while in SLAM mood.

Since you have algae, chlorine may decrease rapidly as algae is being killed off, so test for FC every couple of hours (if you can or if you're at work...morning, lunch time, evening-as frequently as possible). Again, maintain the shock level by adding the correct amount of chlorine/bleach when necessary.

brush..brush..brush... while in SLAM mode.

I know this could be very frustrating, but please hang in there. Just follow the SLAM process rigorously and you'll be golden before you know it.
i use calcium hypochlorite...as i responded to last post - I KNOW everyone recommends liquid chlorine but what am i missing? it sounds SOOO impractical.... Who can lug cases and cases of heavy chlorine from the pool store or other store? they are not available for purchase online as far as i know (for any reasonable price). but calcium hypochlorite comes straight to my door, in 2 days, for a good price from amazon. where do you buy your liquid chlorine from?

other than using the "wrong" type of chlorine, i am trying again...
really hope i'll be more successful this time!
thanks for the encouragement.
 

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