Mustard Algae!

Snowymoon

Active member
May 21, 2007
32
I am another one dealing with this crapper.

I had some brown spots on my walls even. Is it sometimes even on the walls? Aaarrrgg!! :grrrr:

I thought I was rid of it, but it is back now that the chlorine level has returned to normal. Will the stuff ever die? My filter cartridge is yellowish brown every night when I hose it out. :?

I don't wanna shock any more!! I held it there for days. The chlorine held overnight and drifted down to normal...that is when the sucker came back. :evil:

I want to swim, not shock. :shock:
 

Snowymoon

Active member
May 21, 2007
32
CYA is 50 and I am keeping chlorine between 5 and 8 (added 2 points to the range to try to keep MA out). It was around 6 when it came back.

Okay, I am off to read the post you linked to. Thanks! :-D
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
Unfortunately, it does sound like it might be yellow/mustard algae, especially if it sticks to the sides of the pool (pollen and dirt don't usually do that), and usually on the shady side. If it feels slimy, then it's likely to be algae. If you look at it in a microscope, then you can tell for certain. So you don't waste your time, try and determine if it truly is algae. Does a bucket of water nearby also have some of this in it? If you take some of this "algae" in a bucket of pool water, does it grow (have the bucket half covered so only part is exposed to sun)?

Anyway, yellow mustard algae requires a higher FC to keep away -- about 15% of your CYA level so at 50 ppm CYA that's 7.5 ppm FC to maintain. It also takes more to shock. If you lower your pH to 7.2 first, then you need to shock with chlorine at 55% of your CYA level or 27.5 ppm FC (call it 30 ppm FC). Those that have had yellow/mustard algae and shock with lower levels have it come back.

Though we know about the higher chlorine level to keep away the yellow/mustard algae, we don't know for certain if either PolyQuat 60 algaecide or if 50 ppm Borates will keep it away and let you have lower FC levels. We know these options work well to keep away green algae even if no chlorine is present for a time, but we don't have enough info as to whether these are effective at preventing yellow/mustard algae. So other than the "shock it hard" and then "maintain higher FC" advice, I don't know what to say. You could try the PolyQuat 60 and see if you are able to have lower (i.e. normal) FC levels and not have this algae return, but at this point I'm sure you don't feel like experimenting. :(

This algae is apparently often reintroduced into pools via swimsuits (at least that's what I've read) so after you get your pool clear you should thoroughly have your swimsuit washed in hot soapy water (and yes, that'll probably fade the colors, but it'll be worth it knowing that you won't be adding the algae back into the pool).
 

Snowymoon

Active member
May 21, 2007
32
Thanks so much. I appreciate the help.

Wow, I was not shocking at a high enough level, and I am not keeping the chlorine level high enough either. That would explain the issue.

I have never shocked that high before. :shock: However, I am ready to be rid of it. When I keep the chlorine around 8, it decreases, but as soon as it drops below 8, it is back and growing quickly.

:?

I will keep you updated on the progress.
 

Snowymoon

Active member
May 21, 2007
32
I am going to have to shock this weekend. I will go out and try to take photos to share.

It is not a lot, but it is there, even keeping the TC up to 8, and now I think I have some CC as well.

I have put off shocking not to lose swimming time, but it will be done this weekend.
 

Snowymoon

Active member
May 21, 2007
32
I did the best I could for photos.

Here is from a bit of a distance.



Here it is close up.



Here it is even closer, though it is blurry.

 

Snowymoon

Active member
May 21, 2007
32
So if I shock and maintain at 8 and it still returns, I should try the polyquat? I have some left over from last year.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
Sure, lower the pH to 7.2, shock at 30 ppm FC and hold it for at least 2 days (3 is better), then maintain 8 ppm FC after that. If it comes back, try the PolyQuat 60 and let us know if it helps keep it away.
 

Snowymoon

Active member
May 21, 2007
32
Will do, and I will let you know how it goes.

:shock: Ruh-oh. That means I have to use the dreaded muriatic acid. :shock: OH, how I wish I could train hubby to do that bit for me. :whip: :angel: :lol:
 

Snowymoon

Active member
May 21, 2007
32
Oh, I also want to mention that IRL, the algae has more of a yellow-brown tint. It appears black-ish in the photos, which is not really true to what I actually see.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
I'm not sure I mentioned it, but you'll want to carefully brush it after you've shocked to be sure it all gets exposed to the chlorine. This algae isn't like black algae so it shouldn't be hard to remove from the wall and with your soft wall surface (vinyl, right?) you don't want to brush too hard. Be sure and thoroughly clean all pool equipment -- anything you would put into the pool -- and your swimsuits so as not to reintroduce the algae back into the pool (if you can help it).
 

Snowymoon

Active member
May 21, 2007
32
The vacuum hose and head as well as the surface skimmer head, I take it? How would I go about doing that? I assume that just hosing them off will not be enough. :shock: Should I submerge them in the pool while it is shocking after I brush the floor and walls?

I will be so glad to be rid of this stuff.
 

Snowymoon

Active member
May 21, 2007
32
Thank you so much for all your help and support.

The pH is down to 7.2 and is ready to go. :-D I will begin to shock tonight.

I can't wait to post about how the algae is gone, gone, gone. :rockon: :party: :party: :party:
 

Snowymoon

Active member
May 21, 2007
32
I have another question. Should I vacuum every morning while holding at shock level?

I also figured I better toss the toys and dip the floats in the pool while shocking as well, but what about the solar cover?
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
You only need to vacuum if you've got lots of debris or dead algae to take out. Yes, put your toys in as well -- pretty much anything you might be putting back in again later. And yes, put the solar cover on. You'll want to remove the cover part of the time so perhaps put it on for one day and off for the next. You want your pool to breath and get exposure to sun to help burn off the combined chlorines that will from from the dead algae, but that's not needed every day and I think one day of exposure to shock levels for your cover would be fine.
 

Snowymoon

Active member
May 21, 2007
32
Rounding up day #2 at shock level. I cleaned my filter cartridge today. Oy. The water around the filter was more clean, but the filter was much more brown. In the bottom of the cartridge area, there was a lot of fine, black dust. Is this all the dead algae? :shock:

Also, should I replace the filter cartridge when I am done shocking before I let the chlorine levels drift back down, or can I switch it out and clean this one? :shock: