Mustard algae

Mustard Algae

Welcome to this forum! Hopefully we will be able to help you out.

Yellow/Mustard algae looks like yellow/mustard colored dust -- it generally does not stick very hard to pool surfaces. It takes more chlorine to prevent it and especially to kill it than for regular green algae that is more common.

Can you post a full set of water chemistry numbers with pH, Total Alkalinity (TA), Free Chlorine (FC), Total Chlorine (TC) or Combined Chlorine (CC), Cyanuric Acid (CYA) and Calcium Hardness (CH)? Of these, the most important we need to know is CYA. If you don't already have one, I suggest you purchase a high quality test kit such as the Taylor K-2006 or a similar FAS-DPD drop-based chlorine test kit that also tests for the other items I listed.

We can then help you once we know how much CYA you have in your water since that determines how much chlorine will be needed to kill this algae.
 
You can, but I'm not sure you can trust their numbers. Not only do some pool stores not do the test accurately, but some even "invert" the number subtracting what they see from 100! Anyway, if you don't have a kit yet, you can certainly take it to the store, but while you are there see if they have a high-quality test kit like the Taylor K-2006 or any kit that tests chlorine using FAS-DPD drop-test plus pH, CH, TA and CYA tests.
 
Re: Mustard Algae

chem geek said:
Yellow/Mustard algae looks like yellow/mustard colored dust -- it generally does not stick very hard to pool surfaces. It takes more chlorine to prevent it and especially to kill it than for regular green algae that is more common.

Hi chemgeek.

How much higher than a regular shock do you need to get rid of mustard algae? Do you also need to shock mustard algea for a longer period?


my cya is 32

thanks,
dan
 
Fortunately with your relatively low CYA of 32 ppm you can do the following to get rid of the mustard/yellow algae:

1) Lower your pH to around 7.2 by adding Muriatic Acid
2) Raise your FC to 20 ppm and maintain it until the mustard/yellow algae is gone and the FC level holds overnight
3) Restore your pH to your desired level (probably around 7.5) with Borax or pH Up.

You will notice that the FC level to shock this algae is higher than the normally recommended 15 ppm from Ben's Best Guess CYA chart or the 12 ppm from the 0.3 column in my table. The number I gave above is around what is in the 0.7 column in my table and was found to be effective for killing this sort of algae reasonably quickly. It should not take any longer than regular algae to get rid of -- that's part of the reason for using a higher shock level.

As for keeping this algae away, you may need to maintain 4.6 (say 5) ppm FC instead of the normally recommended 3.5 ppm or so. However, this is something you can let us know since we've only had a few users have mustard/yellow algae (green algae is much more common, especially on pool opening). You may even be able to determine a level of FC that just barely keeps the algae at bay and that would be useful to know (you would then keep your FC above that critical level).
 
ChemGeek...thanks a bunch for sharing your wisdom :D

I've tried doing some reading on mustard algae and I can't really find much...and what I do find (outside of here and poolforum) is questionable. At least to me. What little I have read I now question if it is mustard algae or pollen. I have already brought the Chlorine up to 20 and ran the aquabug which cleaned up the bottom.

I almost took some pictures today (even before I read this post) just so I would have it to post. If anyone has a picture of what they think is mustard algae, I'd love to see them and think it would help others as well. I will also take some next time I see it.

Let me describe what I see. My pool gets morning shade and full sun from 11:00am on. The substance that I see is what looks like a (maille type) mustard colored, not a French's yellow. It looks as though it a cross between powdery and a slight fuzz appearance that collects in a few of the small recesses on the bottom only. It cleans up very easy.

I (like others here) am a bit obsessive about my pool maintenance. Not a day goes by when my water and pool is not checked...I run the vacuum every other day. So if something is on the bottom...it isn't there for too long. Which is why I'm not sure if the yellow substance would get worse and spread or not. Perhaps I should take a lead from Gregory House and breed it so I could identify it :mrgreen:

thanks...I'll get back to everyone with a picture if possible
dan
 
Here's another thread where the initial posters comments and pictures mimic my situation.

What am I on...day four or five of FC 20ppm or higher and the stuff is back. The more I think about this...the more I wonder if my problem and some of the others is pollen. Well...for right now I'm going to assume it's not...and (I hate to think about it) I'm going to jump in the 68f water and get a sample and see what I can grow.

The water looks great...but also has the same exact deposits that appear in the thread mentioned at the beginning of this thread.

:evil: dan
 
Did you ever check the CYA level yourself after you got your own test kit? Maybe the 32 ppm CYA from the pool store was inaccurate. If your true CYA level were higher, then a higher FC would be required. I believe one of the first user's on the Pool Forum reporting algae hit it with 35 ppm but had a higher CYA level of 50 and we also didn't think of lowering the pH first to make the chlorine effective (so his FC used the "1.0" column in my chart instead). That's my best guess at this point unless what you have isn't algae. We also don't have as many cases with this algae -- we've got quite a few, but not as many as green algae -- so it's possible some circumstances need higher FC than others. I'm betting that the CYA is actually higher, however. You know, if you had a microscope you could look at the stuff and it would be pretty easy to distinguish the two. I wish there were a simple test to use to distinguish -- can anyone think of something?
 

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chem geek said:
Did you ever check the CYA level yourself after you got your own test kit? Maybe the 32 ppm CYA from the pool store was inaccurate. If your true CYA level were higher, then a higher FC would be required. I believe one of the first user's on the Pool Forum reporting algae hit it with 35 ppm but had a higher CYA level of 50 and we also didn't think of lowering the pH first to make the chlorine effective (so his FC used the "1.0" column in my chart instead). That's my best guess at this point unless what you have isn't algae. We also don't have as many cases with this algae -- we've got quite a few, but not as many as green algae -- so it's possible some circumstances need higher FC than others. I'm betting that the CYA is actually higher, however. You know, if you had a microscope you could look at the stuff and it would be pretty easy to distinguish the two. I wish there were a simple test to use to distinguish -- can anyone think of something?

Hi chemgeek (thanks for the response!)

All the levels I have are with Ben's kit...it's all I've ever used thanks to you guys and gals :)

Some of the other previous cases at PF also have me wondering as well...I just don't know right now. I wonder??? I think right now I'm going to (burrrrr) get some samples. Let one sit in the sun, another I will douse with bleach and the last I will see if I can find a cheap light microscope (one of the nephews or nieces may have one. Heck...at this point I may just go buy a cheap one).


Any suggest on the best way to prepare my sample?

thanks,
dan
 
I think I'll also get a 5 gallon bucket filled with water and place it near the pool to see if it could be pollen. If it's falling in the pool...it should certainly fall in the bucket as well.

we'll see...

dan
 
Dan,

Your ideas are brilliant. The reason I thought you might have had the CYA tested at the pool store is that you quoted a CYA of 32. That's pretty good discerning on the test since it's hard to know exactly when that black dot disappears. Usually people say something like 30-40 or 35 or something like that.

As for preparing the sample, just take an eyedropper (or a small spoon) and place one drop of water that has visible algae in it onto a slide and then put the slide protector (small square glass piece) over it. The water will spread out evenly under the slide protector. Then you just put that under the microscope and look. You can easily search the net for pictures of pollen. They look like round balls, sometimes with spikes or rough surfaces. and are not very transparent. You can also look for algae cells on the net, though you'll mostly find green algae, but the mustard/yellow stuff will look similar except for color and will look more like cells -- not so spherical, and will have distinguishable features in it -- green chlorophyll in some places but not throughout the cell. The algae should be far more transparent than the pollen.

I must say again, that bucket idea is brilliant. Reminds me of the idea someone had of using a bucket of water outside the pool to see if the pool had a leak. Evaporation would lower the level in the bucket the same as the pool (roughly -- assuming similar water height and wind/sun access) so if the pool had a bigger drop in level than the bucket, then a leak was likely. One could also check levels overnight, but for a slow leak the bucket idea was great.
 
Hi chemgeek :) I remember reading in one of the posts on PF that the pool owner found some relief from the mustard algae even after the monsoons had let up. This got me thinking of pollen getting knocked off the trees...and not having additional problems until the next "batch" of flowers open up. I'd also be interested to see when the problem first starts...and when it ends. I've been trying to look at the various posts...but it seems that it can be a persistent problem for one to two months. Which is similar to pollen problems from many trees, bushes and weeds.

I did get to go swimming today :? The water was a bit cold at first...but I did get used to it. I Used my Pool water sample bottle with the dropper tip. I just squeezed the bottle empty of air before going into the water and then used the small vacuum to suck up the small samples I took from the bottom of the pool. It worked fairly well. But the substance would quickly vanish into the surrounding water if I approached to fast. But I was able to get two glass jars filled with a mixture of pool water and just a little bit of the substance.

So what does it look like? Well...I've still got to let it settle a bit. But it is looking like small rounded granular...ummm pollen shaped individual balls. I was surprised because of the appearance from the top of the water which was a bit fuzzy (and algae like).

I will keep an eye on the samples, the pool and the bucket.

dan
 
gone fishin'

i've been reading this thread with interest...

we've just had a 24' agp installed in michigan...the water temp has been very cold (just now hitting 58-60 degrees).

since install, we've had what looks like a reddish-brownish sediment with a slight yellowish hue collect in patches over the bottom of the pool (nothing on the sides and the water is very clear).

i have vacuumed to waste 5-6 times, but the sediment always returns. (although i replenish the water from well water supply & some sediment could be introduced from well water)

i have the taylor 2006 kit and my numbers have been fine.

i'm thinking now that:

(1) it's really sand and maybe i have a cracked lateral in the sand filter, but, it looks too fine to be sand.

(2) residual fine dirt that was somehow introduced inside the sand filter upon installation and is now being slowly reintroduced into the pool.

(3) mustard alagae? it just doesn't strike me as algae....almost looks more like very fine reddish dirt powder...i thought mustard algae would have some sliminess to it....also, i thought the water has been way to cold for mustard algae to even start or grow.

(4) sediment introduced from well water? pollen or dirt introduced to the pool itself (not from the filter)...we've had a few wasps/yellow jackets/dirt dobbers flying around, some of them building their mud nests...probably not likely...lol.

not sure how to first approach this....don't really want to tear the filter apart and inspect laterals if i don't have to....

any ideas?
 
holemania said:
gone fishin'

(4) sediment introduced from well water? pollen or dirt introduced to the pool itself (not from the filter)...we've had a few wasps/yellow jackets/dirt dobbers flying around, some of them building their mud nests...probably not likely...lol.

not sure how to first approach this....don't really want to tear the filter apart and inspect laterals if i don't have to....

any ideas?

You are almost always going to have some dust, pollen etc. landing in the pool that will settle in the bottom. Sometimes it's residue from the decking that gets in the water. The wind carries a surprising amount of crud along with it.
 
in these pics, it looks more yellow than it does to the naked eye...

IMG_3117.jpg



IMG_3118.jpg



thanks for any feedback!
 
ok...jumped in 60 degree water this afternoon with goggles and eyedropper to get some samples.

the reddish-brownish patches on the pool bottom mostly appeared to vaporize when i disturbed them, but using the eyedropper, i was able to "suck up" some samples...it almost seemed fibrous or "pulpy like".

once i colleted some of this in a jar, i let it settle and then poured the sample through a white paper towel.

i have to say it sure doesn't look like sand....seems more like a gummy dirt when concentrated together.

could this be pollens, seeds, etc. brought in by the wind to settle on the bottom?

i still don't know...

but, i'm pretty sure it's not sand or mustard algae.
 
also, just ran my numbers this evening:

FC = 9.0 ppm
CC = 0
pH = 7.2
TA = 90 ppm
CYA = 20 (almost off the scale, but guessing this pretty close)

i think i need to bump up pH a little (16 oz. of borax??)

and maybe continue to use tri-chlor tablets in automatic chlorinator until CYA rises some more?

any advice appreciated!


i'm planning on getting some panty-hose socks and trying to fit them between vacuum hose & vacuum head, then vacuum up the "pollen" or fine dirt on the bottom of the pool.

i'll post how it works out.
 

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