Is it the dread mustard algae?

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
14,657
Houston, Texas
Groan! :hammer: Didn't keep up with my chlorine (or chlorine adding)testing for the last few weeks. Since the water has been clear and below 60 degrees I didn't think I would have a problem. But I come home yesterday and find a bright yellow ring around the waterline of the pool! :hammer: It can't be pollen, there is nothing in bloom right now! Is it the dreaded mustard algae? I'll try and get a picture when the rain slacks off. Water is still quite clear. Going to test right now! :hammer: :hammer: :hammer:
 
There are actually a number of trees pollinating right now including ash, juniper, some pines, and quite a few oaks. There are also some grasses pollinating as well. The Houston Metro area pollen counts are crazy high with tree pollen though.

Is the yellow "stuff" just in a ring around the surface, or are you seeing on the surfaces below the waterline as well?

Have you run any tests? It would be interesting to see if your FC holds through the night. That usually tells the story.
 
I just tested my chlorine and it is at 1 and with my cya it should be in the 7 - 12 range. :oops: I do have a huge live oak that hangs over my pool, I just haven't seen any signs of life from it yet. It is just a ring around the waterline on the liner,skimmer and ladder. I don't see anything that looks like grit or sand in my pool.
 
zea3 said:
I just tested my chlorine and it is at 1 and with my cya it should be in the 7 - 12 range. :oops: I do have a huge live oak that hangs over my pool, I just haven't seen any signs of life from it yet. It is just a ring around the waterline on the liner,skimmer and ladder. I don't see anything that looks like grit or sand in my pool.
See if you can collect a sample -- evaluate for texture, granularity and resistance to undiluted liquid chlorine or bleach. If it's slimy, irregular and loses form and color upon application of chlorine.... well, you know what to do. Otherwise, it's probably wind-blown pollen or other debris.
 
We've had some rain today, enough to raise the water level about a 1/2" and the yellow stuff rose with the water line. I just put in my last jug of bleach and I felt the yellow stuff. It is not slimy, but seams to be powdery in texture and looks powdery in the water when it is rubbed. Too dark to take pictures right now.
 
Nice and sunny out today. Now that I have gotten a good look, it does appear to be pollen. Yay! My oak tree is budding! Very tiny but visible in strong daylight. I am very relieved! And I'll keep on top of my chlorine use from now on! :oops: :-D
 

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zea3 said:
Nice and sunny out today. Now that I have gotten a good look, it does appear to be pollen. Yay! My oak tree is budding! Very tiny but visible in strong daylight. I am very relieved! And I'll keep on top of my chlorine use from now on! :oops: :-D

What were your chlorine numbers when you noticed the ring around the surface...My big maple in the summer is always throwing pollen into my pool. when the pump is off and the water is calm early morning or late afternoon do you see a dust on the surface of your calm pool...If so than it is probably just pollen or dust...plus mustard algae will usually be along the bottom or on the shady side of the pool moreso than around the top...

Do you have globs of the dust on the bottom of the pool too?
 
I had around 1ppm for my chlorine when I should have 7-12. I did not see piles of dirt and my water was still pretty clear. I thought it might be mustard algae since that is what I was told I had last year before I found TFP. It is dry and powdery to the touch and I did see a layer of "dust" floating on the surface this afternoon after the water had been still all day.
 
zea3 said:
I had around 1ppm for my chlorine when I should have 7-12. I did not see piles of dirt and my water was still pretty clear. I thought it might be mustard algae since that is what I was told I had last year before I found TFP. It is dry and powdery to the touch and I did see a layer of "dust" floating on the surface this afternoon after the water had been still all day.

I'd have to say you have pollen...but I would get the chlorine up to your normal level anyway...If you are concerned about the Mustard Algae, than bring your pool up to shock level for Mustard Algae and see if it holds...if it holds over night than I would say you have nothing to worry about. I have never heard of Mustard Algae sticking on the surface or on the water line...If the suface looks dusty than I would say itis your tree blowing pollen into your pool. One thing you can do is put a filter sock in your skimmer basket and it catches all that pollen and keeps it from running through your filter and back into the pool...it is really tiny and can get recirulated...On my pool it sinks overnight because I don't run the filter at night...and then it collects in the little divits on the bottom of the pool. And this is why people think it is mustard algae...I have a sample that I took two summers ago and it never grew...it just stayed dusty...It doesn't grow itjust collects but for those of us with sparklypoolitis...it makes us crazy! :grrrr:
 
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