What IS this stuff? Algae, pollen, dead algae??

amy6152

Member
Apr 4, 2017
21
Rochester, NY
I need help determining what I'm dealing with. I have a greenish/yellowish substance collecting at the bottom of my pool (not the walls) in considerable quantities. I've been reading all the threads on mustard algae and pollen, so I know it doesn't sound like mustard algae - no difference in the shaded bit of the pool - distribution seems to follow normal circulation patterns. But it's definitely GREENISH YELLOW and I have a very hard time understanding how anything can be green at a SLAM level (19ppm, my CYA is 49). If it's pollen, I find that super strange, as we've never had anything like this in our pool in the four years we've had it. If you touch it with your foot, it disappears into a green poofy cloud. Something's alive in there, as I'm still burning through chlorine at around 7ppm/day. Would regular algae still be green on day three of a SLAM? That seems crazy to me. I vacuum and things seem better, then in the morning we're back to square one. What am I doing wrong? Should I vacuum to waste?

FAS-DPD test kit
16k gallon pool
ph 7.2
sand filter
 

Texas Splash

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Jun 22, 2014
31,596
Texas, San Antonio/Marion, South-Central Area
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Everything you describe sounds like algae, but your CYA number is odd. Not what we expect from a TF-100 or Taylor K_2006C test kit. How did you come up with 49? That will be key.
 

amy6152

Member
Apr 4, 2017
21
Rochester, NY
Just eyeballing it with the scale on the side of the tube. You know, the one where you add the water/reagent mix until you can't see the black dot anymore? It's just under 50.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
31,596
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Gotcha. :goodjob: Since the chemistry looks good for a SLAM Process, you might need to look carefully for hidden locations of algae. Do you have a ladder or hollow steps? Maybe a light with a hollow niche behind it? Main drains can also be a source of algae.
 

Dtkokay

Well-known member
Dec 31, 2019
385
Houston, Texas
Just eyeballing it with the scale on the side of the tube. You know, the one where you add the water/reagent mix until you can't see the black dot anymore? It's just under 50.

Just an FYI that the CYA test results should be rounded up to the next 10. In your example, if you get a result of "49" then round that up to 50. The test isn't that precise because of it's subjective nature, and you're better off erring on the side of reading the CYA on the high side.
 

kellyfair

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Jun 29, 2016
4,765
Tampa, FL
Pool Size
7000
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Vinyl
Chlorine
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Intex Krystal Clear
How often are you testing and raising FC? (Use 20 as your target).
 
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