Losing the Resistant Mustard Algae Battle

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pharmcoder

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May 17, 2016
78
Lancaster, Pennsylvania
I desperately need help with mustard algae.

My pool chemistry as of 10 AM today using Taylor K2006 and TF100 kits:

FC = 6
CC = 0.5
pH = 7.2
TA = 70
CH = 170
CYA = guess of 10 (keeping trichlor pucks in floaters and based on FC
readings). The test has slight cloudiness when done, but doesn’t hit
the 20 mark on the TF100 CYA test tube

I apologize for how long this is going to be. This is what has been the status to date:

Up until this year, the pool has been easily maintained using TFP methods with a max of 3 green algae blooms (1 due to my surgery and the other 2 when opening in the spring).
We opened the pool on May 7th this year and within one week, brown sandy streaks and blotches started formed on the shallow end floor, in skimmer bases in front of weirs, and all around the crease where the floor meets the wall in the deep end.

It's a 39,000-gal pool vinyl liner pool. We have a VS pump that I have been leaving on 24/7 running at 50 gal/min (2400 RPM). The filter is a 72 sq. ft DE grid filter (installed this May). All returns are pointed downward and the main drain is 50% open.

I have been keeping 3 floaters in the pool with 4 of the 3 in. trichlor pucks in each of them because I am keeping the SWG off while adding chemicals and my CYA has been trending down.

I had added 12.5% liquid chlorine shock from May 16th through July 2nd to maintain a free chlorine (FC) level of 15 while keeping the pH around 7.3-7.6. I tested the chemistry every 2 hrs. initially, and then 3 times a day as I became familiar with the situation.

The TA has drifted down from 90 to 70 and the CYA dropped from 30 to 10 (best guess). The CC has ranged from 0 to 0.5, but no higher. And...my phosphates have increased from the baseline of 200 to 750. So far, the test for nitrate has been negative. There are no metals in the pool and no algaecides have been used.

I followed the SLAM OCLT procedure before starting the Mustard algae battle and have done 5 successful OCLTs throughout the process.

I have been keeping debris out of the pool and brushing the whole pool (skimmers included) every day...sometimes twice a day (I missed brushing June 11th - June 15th , but did remove debris) and I have been sanitizing any hoses, poles, brushes, etc. I also removed and sanitized the ladder from the deep end (have not put back in pool yet), vacuumed to waste 3 times, and I have back-washed the filter 3 times.

There are 4 fiberoptic lights that fit snugly with the vinyl liner.

It seemed to disappear in 1 - 2 weeks initially, but as soon as the FC fell below 7 PPM (with daily brushing), white sandy patches showed up in the same places in the shallow end only.
So, I kept repeating the process where I continued for a week and then let the FC drift to near 7. Without fail, I would see the same patches again.

A week ago (around July 2nd), I decided to switch to Cal-hypo 73% since my CH was 130. The patches now show up at a FC level of 12 and they are darker, in the original spots and spreading! I am SO frustrated!

I would prefer to not use algaecides, but I’m, getting desperate…. half of the summer is gone, and nobody has been in the pool

Help? Thank you.
 
Welcome! You're in the right spot.

You're going to have to SLAM your pool. However, before you do that, you should first bring your CYA up to 30 by adding a stabilizer (using the sock method). I recommend you add the granular in a sock and hang it close to your return jet. You can gently massage the sock to dissolve the granular once you have it hanging in your pool (at least that’s what I do). It speeds up the process a bit. Wait 24-48 hours before you retest again your CYA. However, note that you can go ahead and start the SLAM. You don't want to delay that waiting for the CYA to dissolve entirely. That is just booking rooms for the algae to reproduce in.

So as your stabilizer is dissolving to 30 CYA, you will need to bring your FC level to a 12, thus starting the process of SLAMing your pool. Maintain your shock level of 12FC. At the start of SLAM, 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). Again, maintain the shock level by adding the correct amount of chlorine (PoolMath) when necessary. As algae is being killed off, chlorine (FC) will deplete slower and you’ll not need to test so often. Again, do your best to maintain the proper SLAM "FC" level based on your CYA FC/CYA.

Continue vacuuming and brushing pool each day while in SLAM mood. The more often you test and brush, brush, brush, the faster it will go. Once pool is clear, its time to perform the following. Here’s the link: Overnight FC Loss Test (OCLT)

I'll let the experts chime in here shortly if there is more you need to do...
 
Welcome to the forum:wave:

Ask lots of questions and we'll all help. Why are you using two test kits? I am not sure of the condition of your pool.....how does the water look? How do you know you have mustard algae. Sorry, your post is a little tough for me to follow.
 
Wow, thank you for the quick response Mendy48 :)

I will go ahead and bring my CYA up to 30 again. I was trying to hold it where it is with the chlorine puck floaters because of vacuuming to waste and back washing. Since I have liquid instant stabilizer, I am hoping the CYA level will begin to increase faster than 24 hours.

I forgot to mention that I test my FC every night around 10PM and then between 6AM and 7AM every morning. I have had no FC loss through the night or had a CC of more than 0.5 since the middle of May.

All of the chlorine I have been adding has bleached my liner :(. Except for the days I allowed the FC to drift between 7 and 10 in order to test the chemistry and see if the algae reappears from start of process to July 2nd, I have kept FC between 13 and 25.

Should I throw in the BBB towel and add Phosfree and/or an algaecide too? :confused:

Thanks
 
Hi Dave!

I'm sorry about the novel. This has been frustrating.

I have 2 kits because I bought the TF100 and my daughter surprised me with the Taylor kit. I therefore alternate using them. They are indispensable!

My pool water looks like glass, but when I look at the floor I see the sandy dirt patches, sandy dirt lines on the floor and along the liner seams.

I reluctantly accepted it as mustard algae because it turned to a white sandy substance at the beginning of the process, disappeared, and then showed up in the same spots after the FC drifted down to the 7 PPM range. It brushes into a dust cloud easily. It also looks like mustard algae pictures that have been posted:(.

I really don't want to use an algaecide, but I don't know what else to do.

Thanks for responding.
 
You should stay away from chlorine puck floaters and use plain bleach (The plain stuff - no splashless, scents, or polymers. No Clorox or cloromax (no additives)). Or you could get Liquid Chlorine 10% from Walmart...same stuff. If you follow the FC/CYA, your vinyl liner will not bleach. When pouring your bleach or LC, pour it gently and slowly at the return jets. You should follow the SLAM procedure to get rid of the algae in your pool. You may have algae lingering around still.

Use granular stabilizers to add CYA to your pool. Use the sock method as mentioned earlier to get your CYA to 30. Though you have no FC loss, your CC is more than 0.5...if I read that correctly? Nevertheless, you have to follow the FC/CYA at all times. My liner is very blue and I follow the FC/CYA and make sure I pour my liquid chlorine slowly near the return jet.

Stay away from Phosfree and/or an algaecide as well.

My liner!
IMG_0004.jpg

pharmcoder said:
Wow, thank you for the quick response Mendy48 :)

I will go ahead and bring my CYA up to 30 again. I was trying to hold it where it is with the chlorine puck floaters because of vacuuming to waste and back washing. Since I have liquid instant stabilizer, I am hoping the CYA level will begin to increase faster than 24 hours.

I forgot to mention that I test my FC every night around 10PM and then between 6AM and 7AM every morning. I have had no FC loss through the night or had a CC of more than 0.5 since the middle of May.

All of the chlorine I have been adding has bleached my liner :(. Except for the days I allowed the FC to drift between 7 and 10 in order to test the chemistry and see if the algae reappears from start of process to July 2nd, I have kept FC between 13 and 25.

Should I throw in the BBB towel and add Phosfree and/or an algaecide too? :confused:

Thanks
Click to expand...
 
I really don't want to use an algaecide, but I don't know what else to do.
Click to expand...
Another poster on the forum has an almost identical thought but I don't understand why. An important tenant of what we teach is not putting things in your pool when you don't know or understand the outcome? Phosphates remover and algaecide will do nothing for your condition. forget them for this purpose.

A pic of the debris would help but it doesn't sound like mustard algae. Mustard would appear yellowish/greenish and on your pool walls....typically on a shady side.

My suggestion is that you SLAM the pool. Pay VERY close attention as to how the SLAM come to an end. There are three criteria you MUST meet...

A. Pool water should be crystal clear with no sign of algae anywhere
B. CC's test result should be .5 ppm or less
C. You should not lose more than 1 ppm FC overnight.

It seems like you may have met some or even all of these criteria but the SLAM is just about 100% effective when you are true to the instructions. Chlorine is your answer.....not phosphate remover or nitrites or metals or algaecides.

SLAM your pool with proper chlorination and I believe your pool will be remarkably clear.

PS - twice you referred to the debris as "sandy". Is it gritty? can you pinch it between your thumb and forefinger and feel the grit?
 
Dave,

I couldn't get any between my fingers, but when smearing it with my finger on the steps an skimmer it didn't feel gritty.

From mid-May through 1st week of June, I did the SLAM at CYA =30 and FC = 25. Once the CYA dropped to 20, I kept the FC at 15 up until 3 days ago. I've since let it drop to 12-13 as a target (I let drop to between 7 and 10 to check chemistry periodically). Today, it was at 6 because of my frustration level.

Everything about passing the SLAM was met while the FC levels stayed above 13, (BUT....even though the pool surfaces looked clean and clear, brushing would produce dust clouds).
 

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Those are good pics...Thanks! It looks like plain ole' dead algae to me so somewhere, somehow the FC didn't get it all.

It is common for newbies to think they have VERY special algae which doesn't respond but that is not the case. Some may take a little more FC, a little more time, a little more cussing but in the end it all capitulates to chlorine and your pool will clear.

If you could brush this stuff up, you did not complete your SLAM.

Again, without looking back, I would re-SLAM the pool and make absolutely certain you hold the FC long enough to get everything.....ie, you pass the three SLAM ending criteria. Pump running 24/7, brushing, vacuuming, testing and running your cleaner are all part of the SLAM.
 
Thanks Dave,

To recap:

Raise my CYA to 30 (I was hoping to keep it where it was with the pucks due to all of the vacuuming and back washing soon to come)
SLAM by maintaining FC of 20
Brush and vacuum to waste daily

until there are no more dust clouds as well as not losing more than 1 PPM overnight with less than 0.5 CC

Btw...the patches have gotten more brown with a slight yellow hue and there are more.....ugh!!

Thanks for the advice
 
With a CYA of 30, you FC shock level will be 12 and not 20. See FC/CYA. Maintain your SLAM at 12 FC until you pass all 3 criteria. By raising your FC to 20 with a CYA of 30, you run the risk of bleaching your liner. Stay with the chart above for sure.


pharmcoder said:
Thanks Dave,

To recap:

Raise my CYA to 30 (I was hoping to keep it where it was with the pucks due to all of the vacuuming and back washing soon to come)
SLAM by maintaining FC of 20
Brush and vacuum to waste daily

until there are no more dust clouds as well as not losing more than 1 PPM overnight with less than 0.5 CC

Btw...the patches have gotten more brown with a slight yellow hue and there are more.....ugh!!

Thanks for the advice
Click to expand...
 
Yeah! I just know that if your CYA is at 30, you will need to follow the FC/CYA to reach the recommended FC shock level and maintain it there. Where is the information from ChemGeek? I may be missing something here...

Update: I see what you're saying...you're correct. If you did the normal SLAM the standard way, now raise your FC level up an extra high mustard algae shock level for 24 hours. Follow this chart here.


 
Hi Mendy48,

Okay....thanks!

Since it all came back with a vengeance today, I have to start it all again :(

I'll do the SLAM at FC of 12 and CYA of 30 until dust clouds are nonexistent, and then I'll do the 24 hour Mustard Algae FC of 18.

I have spent almost every day on this since mid-May. Brushing this pool kicks my hind end (especially on hot humid days).

I can't believe how quickly this stuff came back, especially when it seemed as if I was nearing the end of the process....ugh!
 
Keep up the good work. You’ll get to the finish line in no time.

pharmcoder said:
Hi Mendy48,

Okay....thanks!

Since it all came back with a vengeance today, I have to start it all again :(

I'll do the SLAM at FC of 12 and CYA of 30 until dust clouds are nonexistent, and then I'll do the 24 hour Mustard Algae FC of 18.

I have spent almost every day on this since mid-May. Brushing this pool kicks my hind end (especially on hot humid days).

I can't believe how quickly this stuff came back, especially when it seemed as if I was nearing the end of the process....ugh!
Click to expand...
 
Update on my Mustard Algae 2 battle:

I have been at this for a week since I last posted.

I raised the CYA to 30, but kept the FC at 15 for 4 days. After 4 days, I upped it to 18 because the algae continued to return in the same spots and seemed to be getting a little more aggressive. At 18, it seemed to improve. After 2 more days, I decided to try a FC of 25. At that level, it takes longer to show up, there is a considerable decrease in spots, and they are smaller.

I brush everything in the pool anywhere from 2 to 4 times a day. With an occasional vacuuming to waste.

My husband and I broke down the brand new DE Grid filter and soaked the grids, the other Grid hardware, and the housing in a 10% bleach solution about 5 days ago.

I check my FC and CC every night around 9:30 PM and in the morning between 6 and 7 AM.

At night, boat swimmers visit the pool and peck at the algae that is invisible until morning.

I finally let my FC ease down to 8 yesterday because I wanted to test the chemistry. I tested at home with the Taylor K2006 first and then took a sample to the PS.

Test results as of yesterday:

FC = 8 (our number agreed)
CC - 0.5 (our number agreed)
pH = 7.4 (our number agreed)
CH = 150(PS) and 180(Taylor)
TA = 72 (our number agreed)
CYA = 28 (PS)
no metals
Phosphate = 466 (PS) and my test looked like it was between 500 and 1000
Salt = 2000 (PS)....it was 2200 a week ago(?)

I keep my manual vacuuming equipment, pole, brushes, and nets in the shallow end of the pool. I have not reinstalled the ladder yet.

I've noticed pictures in other posts that look very similar to the beast I'm at war with.

My husband wants me to just close the pool. I have spent hundreds in bleach, acid, and chemistry reagents. And...my days are consumed with the pool. He's tired of it. :(

Help?
 

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