Was searching the internet when I found this site. I hope you can help. Bought our house in November and put in a new liner in late winter. all seemed well until the weather turned hot a few weeks ago. It looked like dirt and brushed and vacuumed away easily, but came right back. We even shocked a few times but the yellow/brown areas kept returning to the bottom and walls of the pool. I think this stuff is mustard algae. After reading here a bit, I realize we never got the chlorine levels near high enough to kill the algae. As soon as I finish this question, I am going to order one of the test kits recommended on this site. I don't understand how I will know how much bleach to add or how long I need to sustain the levels way up there during the "slam" to kill the algae for good. Another big concern is what damage will the high sustained chlorine levels do to my new liner? Thanks so much in advance for your help!
mustard algae, I think
- Thread starter RN1963
- Start date
Howdy...welcome..keep reading, when you receive your recommended test kit you will check a level... cya...this reading is in direct relation on the amount of bleach used during the slam...the folks here will lead you through the process..your concern about the new liner will be addressed..I have a plaster pool...the knowledge here is impressive and cordial...you have come to the right place...pictures are always welcomed...D
Welcome to the forum.
You will use PoolMath, located under the tab on the top left of every page. You will load the size of your pool in PoolMath and then perform your tests in the kit and enter that data into the left column and your target data (where you want to be) in the right. PoolMatch will tell you what to change of each parameter, if any changes are needed.Keep reading the testimonials and DO NOT start your testing until you have read "The ABC's of Pool Water Chemistry" up in Pool School. It's the starting point.
Next, get a good understanding of the SLAM article in Pool School. Pay particular attention to what the letter "M" stands......for 50% of newbies miss it.
This all will be a real eye opener....we're glad you are here.
"I am going to order one of the test kits recommended on this site"
Now THERE'S somebody who truly wants control of their pool. Welcome!
Now THERE'S somebody who truly wants control of their pool. Welcome!
I just received my test kit today. It took longer than I thought. My son tested the water but only the CYA and FC. The CYA = 60 and The FC = 12. The water looks very cloudy and the pool is loaded with mustard algae spots. When I brush the algae puffs into a brown/yellow cloud. I have not done much except add a little bleach in the last week. Please help me clear this up. Can it be done without bleaching out my new liner?
Congratulations on the test kit 
Now we need for you to do a complete test and post results here. We need:
FC
CC
pH
TA
CH
CYA
There is a link to a youtube video for the test kit in my sig. Please verify the CYA test. You can pour the solution back into the bottle from the tube and retest several times if you need to do so. Lots of us do that.
Now we need for you to do a complete test and post results here. We need:
FC
CC
pH
TA
CH
CYA
There is a link to a youtube video for the test kit in my sig. Please verify the CYA test. You can pour the solution back into the bottle from the tube and retest several times if you need to do so. Lots of us do that.
ok here it is. We are adding some water to the pool now. The algae looks worse this morning.
CYA = 65
FC = 8
CC = 0
CH = 290
PH = 7.5
TA = 100
CYA = 65
FC = 8
CC = 0
CH = 290
PH = 7.5
TA = 100
Ok, so I think I figured out pool math. I added bleach all day yesterday. Got my FC level up to 28 before bed and at 5:30 this morning the level was still close to that. My plan is to add chlorine every hour this morning x3 before my son has to go to work at 10am. It is going to be hot today around 100 degrees. No one will be home till around 5pm. Im sure it will drop during the day. Should I try to get it up to the mustard algae kill level before I go to bed tonight or just to the regular shock level for one more night? Thanks for your help!!
Sounds like you're on the correct path.
1) Don't just "add chlorine every hour", test before adding, and use pool math to determine how much to add. Post FC and TC test results if you don't understand anything, or just post them anyway - it will let us spot any issues.
2) Brush, brush, brush. Some algae forms a protective layer against chlorine, brushing helps to break the protective layer.
3) Please understand that bringing FC up to Mustard Algae level alone isn't going to kill algae faster, or reduce the need to brush - the key is to keep "kicking" the algae, rather than giving it a hard kick and calling it done
4) You can raise the FC level slightly above SLAM (but not above Mustard Algae levels) before leaving for the day to account for chlorine burn-off due to the sun
5) For night time, raising the FC is similar to day, except FC will not drop due to sunlight at night - so dosing FC at night helps reduce algae
6) If you can, test and dose as often as possible after sunset and before going to bed
1) Don't just "add chlorine every hour", test before adding, and use pool math to determine how much to add. Post FC and TC test results if you don't understand anything, or just post them anyway - it will let us spot any issues.
2) Brush, brush, brush. Some algae forms a protective layer against chlorine, brushing helps to break the protective layer.
3) Please understand that bringing FC up to Mustard Algae level alone isn't going to kill algae faster, or reduce the need to brush - the key is to keep "kicking" the algae, rather than giving it a hard kick and calling it done
4) You can raise the FC level slightly above SLAM (but not above Mustard Algae levels) before leaving for the day to account for chlorine burn-off due to the sun
5) For night time, raising the FC is similar to day, except FC will not drop due to sunlight at night - so dosing FC at night helps reduce algae
6) If you can, test and dose as often as possible after sunset and before going to bed
Ok, this seems like a nightmare to me! The pool looks worse tonight. The water is very cloudy and very green in the deep end. The shallow end is not as cloudy but continues to have very heavy algae on the sides and floor. It poofs heavy yellow brown as it has all along. None of it seems to be stuck to the liner, but for the most part now, the whole pool is affected, all 4 walls and the floor are covered. I have brushed well twice today. How long am I supposed to sustain these high levels? The FC is at a 40 now with O combined chlorine. The level dropped to 23 at the lowest today while no one was home. The mustard kill level was 40. Should I hold still at 40 or go alittle higher tonight? Thank you for your help!
Looking cloudy and FC drop - don't panic. This indicates that algae is being killed. It gets worse before it gets better.
Is your pump running? If not, it needs to be running, we recommend letting it run 24/7 during SLAM.
Is your pump on "recirculate" or "filter"?
With regard to FC levels - pool store recommendations of 3FC are from the old days before CYA was discovered. CYA buffers the FC to reduce how harsh it is, that's why our recommended FC levels are proportional to CYA levels.
Combined Chlorine (CC) will be all over the place, just report it - if there are any issues we would let you know.
Mustard SLAM is the maximum we can recommend, especially with a vinyl pool - our experience shows it is high enough to kill off the persistent algae, yet low enough to prevent damage to the vinyl.
Also, can you please post pictures?
If you are using a smartphone or a tablet, you could use Tapatalk to post pictures directly - visiting this site with your smartphone/tablet automatically prompts you to install Tapatalk if you have not already done so.
Is your pump running? If not, it needs to be running, we recommend letting it run 24/7 during SLAM.
Is your pump on "recirculate" or "filter"?
With regard to FC levels - pool store recommendations of 3FC are from the old days before CYA was discovered. CYA buffers the FC to reduce how harsh it is, that's why our recommended FC levels are proportional to CYA levels.
Combined Chlorine (CC) will be all over the place, just report it - if there are any issues we would let you know.
Mustard SLAM is the maximum we can recommend, especially with a vinyl pool - our experience shows it is high enough to kill off the persistent algae, yet low enough to prevent damage to the vinyl.
Also, can you please post pictures?
If you are using a smartphone or a tablet, you could use Tapatalk to post pictures directly - visiting this site with your smartphone/tablet automatically prompts you to install Tapatalk if you have not already done so.
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