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

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
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!
i see that your mustard algae description IS different than what i have. "as a layer of silt" and "nickel sized spots" sounds different that the layer of yellowish streaking on bottom or slope of pool that i see. i sure so after years of thinking i had mustard algae (because a tech told me so over the phone...) i think i am coming to realize that i really don't have it after all and am instead struggling with plain old algae. I really do hope you are finished you battle!

Please advise - why are you closing tomorrow, wouldn't the temp of the water go down to about 60 in just another 2-3 wks? my pool was 65 degrees today and i thought that was the whole point in waiting for long to close (so that we could open cleaner). Also, i'm wondering why you would want to lower the chlorine content of the water. please advise, because i wanted to make sure there was plenty of chlorine in it when i closed. is that wrong?

Lastly, thank you for the advice on the liquid chlorine. My issue is the extra trip to the store and the weight of the item and the quantity i have been using. Sounds like an awful lot of work. Can you explain why you found it superior? Also, did you find it difficult to have to add the chlorine daily (instead of putting 3" tabs into a chlorinator and then being done for the week)? I really would like to hear because i see that liquid is the recommended chlorine again and again, but i have only used it in limited amounts and never thought it was very practical.
 

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
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!
also, can you clarify? i thought you said that in your 2 wk battle, every few days you had the algae again. but this post makes it sound like you finally beat the algae. so after the two weeks have you determined that you are INDEED algae free?
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
11,624
Evans, Georgia
When you add CalHypo, as handy as the little packets may be, you're also adding a lot of probably unneeded calcium to your pool also. When the calcium level gets too high you can start seeing it build up on the walls and sometimes make the water cloudy. And in areas of the country where the water is already "hard" adding yet more calcium is ridiculous!

At TFP we're all about using the best product for the job and one that doesn't cause other problems down the road. Hence we usually always recommend liquid chlorine when battling algae. The only thing it leaves behind is a bit of salt and an empty jug for the recyling can.

For the routine chlorine needs some folks don't mind getting a jug or two of bleach from the market weekly, while many of us swear by our salt water chlorine generators.

But solving an algae outbreak isn't a matter of just tossing one package of CalHypo in. Its a matter of adding enough so that you reach a necessary FC level and then *maintaining* that level until the pool is cleared entirely. If your pool's calcium level is so low that you can handle a lot of added calcium... go for it. Remember that vinyl pools don't need any calcium in the first place.

Maddie :flower:
 

proavia

LifeTime Supporter
TFP Guide
Feb 6, 2015
1,628
Chandler AZ
I may have missed it - what test kit are you using?
What is your current CH level? Calhypo adds calcium.
How often are you brushing the entire pool?
How often are you testing?
It would be best to post a complete set of test results from one of the recommended test kits.

FC
CC
pH
TA
CH
CYA

You want to be done maintaining the pool for this season? Follow the SLAM Process to the letter. No shortcuts, no guessing. You are done when you pass ALL 3 criteria.

Liquid chorine - sodium hypochorite - can be purchased at most any grocery store. It's called bleach - same ingredients at liquid chlorine at a lower percentage (usually 6% or 8.25%). If you use bleach, make sure it is not scented, not low splash and that it doesn't say anything about polymers or fabric protection on the label. Chances of having liquid chlorine/bleach delivered to your door is extremely slim due to commercial/DOT transportation requirements.

If you want to be successful in eradicating the algae - follow the SLAM Process, lug the jugs, do the work and you will succeed. It's not going to be instantaneous, but it will work.
 

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
I may have missed it - what test kit are you using?
What is your current CH level? Calhypo adds calcium.
How often are you brushing the entire pool?
How often are you testing?
It would be best to post a complete set of test results from one of the recommended test kits.

FC
CC
pH
TA
CH
CYA

You want to be done maintaining the pool for this season? Follow the SLAM Process to the letter. No shortcuts, no guessing. You are done when you pass ALL 3 criteria.

Liquid chorine - sodium hypochorite - can be purchased at most any grocery store. It's called bleach - same ingredients at liquid chlorine at a lower percentage (usually 6% or 8.25%). If you use bleach, make sure it is not scented, not low splash and that it doesn't say anything about polymers or fabric protection on the label. Chances of having liquid chlorine/bleach delivered to your door is extremely slim due to commercial/DOT transportation requirements.

If you want to be successful in eradicating the algae - follow the SLAM Process, lug the jugs, do the work and you will succeed. It's not going to be instantaneous, but it will work.
hey! why didn't i see that there were more responses to my posts?
i am using taylor kit 2006 (?) not the K-100 (?)
I have not tested the calcium b/c i thought that was not necessary for a vinly pool

Other test results this week offhand were about
FC 30+
CC .02
PH 7.2
CYA 70
and i'm not sure TA - about 70 i think.

I am absolutely on the verge of giving up. i AM following the SLAM to the letter as far as i know.

I adjusted my PH to 7.2. I turned on pump Sunday morning and left running and it still is running. I raised my FC to about 35 (with CYA of 70 i need 28 but i didnt want to risk having it slip while i was at work).
I spend 1.5 hrs on sunday brushing and vacuuming the pool. I checked the chlorine levels twice a day sunday, monday, tuesday. I brushed the entire pool every day.
my chlorine has held in the 30s.

i STILL have my initial two questions - why do i still brush up a bit of yellow dust from bottom of pool as late as this morning? and why don't i see dead algae dropping to the floor.
i am brushing, vacuuming and using high dose of chlorine, why is it not killing every last spec of algae?

additionally, SLAM procedures assume that i will rapidly lose chlorine at the beginning. i did not. i do not seem to have very much algae at all and never saw any significant reduction at the beginning of this process. It seems like this little bit of algae just won't go. i have never seen combined chlorine of more than .2 during this whole process.

Its so frustrating because this whole idea of leaving the pool open the extra two months was to save myself the effort and money next spring, yet in the meantime i have spent so much more on electricity and chlorine than i would have in the spring! never mind the insane investment of time.

with all the chlorine i have used in the pool these last weeks i could have easily cleared up a very green pool!

I cannot see if i pass an overnight Chlorine loss test because since my chlorine is so high, when i test the same water sample in succession i get different results. i called taylor and asked what is wrong with their kit - i keep getting different results and he told me that a 10% difference is normal. So with chlorine over 30ppm, i may have a reading once of 33 and then next of 36ppm etc. So its really hard to know if i am losing a bit of chlorine overnight. But otherwise pool is clear, no combined chlorine (or .2cc) and the issue continues to be that when i brush a see a bit of yellow dust cloud into the water and i want it GONE. from past experience, if i let go for a day or two it will spread and spread...

HELP!!! what am i doing wrong. everyone keeps saying - do the SLAM but i just can't seem to get it to work.
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,950
NW Ohio
Other test results this week offhand were about
FC 30+
CC .02
PH 7.2
CYA 70
and i'm not sure TA - about 70 i think.

I am absolutely on the verge of giving up. i AM following the SLAM to the letter as far as i know.
I do not understand how you feel you are following SLAM "to the letter" yet you are keeping your FC well above the target. It doesn't look good when the simplest part of the process, "aim for this number", is being ignored...
 

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
1) i want my FC to be higher than recommended for 70cya in case my CYA is a bit higher (up to 80cya). Its hard to determine the exact CYA
2) i cannot have the FC slip BELOW the 28-31 recommended and because i am at work all day and the chlorine gets used up while i am out, i want to make sure there is enough to make sure that it remains above targeted amount at all times.
3) remember, i am having trouble getting an exact chlorine reading with 10% error expected. i do NOT want any reading to dip below 30ppm, i'm not confident enough that the chlorine level is high enough.
 

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
I do not understand how you feel you are following SLAM "to the letter" yet you are keeping your FC well above the target. It doesn't look good when the simplest part of the process, "aim for this number", is being ignored...
see this thread:

What is the downside to holding FC a few ppm over target based on CYA level?


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mknauss
Mod Squad
TFP Expert
Bronze Supporter

May 3, 201422,394Laughlin, NV
Aug 10, 2017
$$$$. That is about it. In your case, it is the finite amount of chlorine that your SWCG will create in its life span.

6000 Gallon IG Fiberglass with integrated Spa;Pentair CCP240 Cartridge Filter with Pentair Intelliflo VS Pump and HTR250 heater. IC40 SWG. EasyTouch 4. Dolphin Active20 Robot "Roadrunner", TF 100 Test Kit w/SpeedStir!
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Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
ok, so what would be the issue if you could not test the FC every 3 hrs and therefore made sure it was a bit over the target so that you knew it would not fall BELOW target SLAM amount.
 

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
because i thought that target number is the number at which the algae can't survive. I initially started this thread saying that although my chlorine is kept very high, i still seem to have algae... and i thought everyone was telling me that until i CONSISTENTLY kept the chlorine high enough until it was ALL dead, it would just bounce back and regrow every time i turned around.

what IS the issue with FC that is too high? you are not saying that that is what is causing my algae to STILL be on bottom of my pool on day 5, are you?
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,950
NW Ohio
I am not saying that your FC level is causing algae. I am saying that you are claiming to follow the process perfectly and are posting proof that you are not.

What I am trying to get you to understand is that you are inserting your own ideas in to the process instead of following it as it is written. As such it is not a mystery where the problems you are facing likely originate.

If you follow the process exactly as it is written then it works. If you go your own way then it might not work. How's going your own way working so far?
 

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
i am happy to stand corrected. i did not realize AT ALL that going above the target by putting in whole bags of shock when i needed a chlorine addition was different than SLAM instructions. Its a new idea to me to measure my chlorine by the oz etc before adding and leaving open unused bags... But I also would be very appreciative and happy if someone would PLEASE tell me what else i am doing wrong which is still causing my algae challenges.
 

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
I am not saying that your FC level is causing algae. I am saying that you are claiming to follow the process perfectly and are posting proof that you are not.

What I am trying to get you to understand is that you are inserting your own ideas in to the process instead of following it as it is written. As such it is not a mystery where the problems you are facing likely originate.

If you follow the process exactly as it is written then it works. If you go your own way then it might not work. How's going your own way working so far?
also, are you indeed saying that i can adjust chlorine at 7am to SLAM level - not higher - and then leave during the day and let the chlorine drift below the recommended slam level? this will not allow the chlorine to thrive and regrow?
what is recommended when you are leaving home for many hours? i thought SLAM instructions said that at minimum you can adjust chlorine two times a day. what number should you adjust to in the morning so that you are ok by evening?
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,950
NW Ohio
You aim for the target.

Algae is killed at any chlorine level, SLAM is just the optimal level above which there is diminishing returns on kill rates and increased risk to liners and equipment. I'm not sure where the misconception that algae doesn't die below SLAM level came from, if that were the case we couldn't maintain clear water at normal target FC/CYA ratios...
 

undrwater

Active member
I'm not the OP, but I am working on something similar to both @Chaya and @HSBigDaddy . That is, something that looks like yellow mustard, but seems not so easy to battle. Maybe we have a new resistant strain of algae? <-- sarcasm, btw. :D

Honest question that came up while reading this thread: There seems to be an implication that running a higher than delineated FC during SLAM may have negative repercussions on the process. Is this true? That would be good info to know: "Don't fall into the trap of adding more LC in the hopes that you'll actually be able to go to work and leave your pool's side."

My assumption based on reading here was that the biggest negative impact was to one's bank account.

Perhaps the OP's issue is holding onto the use of solid chlorine?
 

Chaya

Well-known member
Jul 28, 2019
50
Lakewood, New Jersey
You aim for the target.

Algae is killed at any chlorine level, SLAM is just the optimal level above which there is diminishing returns on kill rates and increased risk to liners and equipment. I'm not sure where the misconception that algae doesn't die below SLAM level came from, if that were the case we couldn't maintain clear water at normal target FC/CYA ratios...
ok, i understand the risk of chlorine that is too high. but please explain - if normal target chlorine rates DOES kill algae then why did i have algae growing and spreading with chlorine levels waaay above target but below SLAM levels? and in response to my asking why i was not getting rid of the algae, the answer i got was that i needed to SLAM - which i understood to mean that without much higher chlorine levels, i would not be able to kill the algae once and for all!

but to clarify as well, you are saying it IS ok to adjust to target FC in the morning and then let it fall below that level during the day, as long as i raise it again in the evening?

Thank you for your continued explanations.
 

Danforth

Gold Supporter
Feb 19, 2019
16
Orlando, FL
Hello! I’m no expert and have owned a pool for only a year now. Just tossing out an idea as I can sense it’s been a frustrating experience for you.

Reading through your thread, it seems you’ve maintained some really high chlorine levels for some time. I also notice that your location is listed as New Jersey.

I’ve got a friend in NJ who said that ragweed pollen is really bad there now. It started at the end of August, which roughly tracks with your statement that you’ve been seeing the yellow streaks on your pool floor for about a month.

Given that it doesn’t seem to be responding to chlorine, and apparently isn’t clinging to the walls of the pool, is there a chance this is ragweed pollen in your pool? Do you see it on other surfaces (like your car) or perhaps floating on the pool surface at all?

I don’t have enough experience to tell you how to test that theory, but I’m sure others here do. Just wanted to share that thought since I had just talked to my friend about the pollen problem in your area.
 
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