Mustard Algae Or Pollen. Very Confused! Help!

Nov 5, 2016
6
Phoenix, AZ
Hi all,

First of all, I've read just about everything there is to read about yellow mustard algae. Having a hard time with this though...

I went to Leslie's (before learning about TFP and other helpful sources online) and told them I thought I had algae (yellow/greyish stuff that wouldn't go away). I bought a test kit and also had them run a sample. I got my water balanced out, then they had me follow their algae worksheet to get rid of it. It went something like:

1. Balance pool.
2. Pour in yellow out treatment.
3. Shock pool with 2lbs of their shock bags.
4. Wait 12 hours, shock again.
5. Wait 12 hours, shock again.
6. Use their perfect pool solution to remove dead algae.

I did this twice, and to no avail. The second time, I actually shocked the pool an extra two times in the beginning because I realized the FC was reading zero (I assume that the algae was just feasting on that excess chlorine based on what I've read).

Last night, after my second attempt, the pool looked spotless. I mean clear as day, no signs of algae, chlorine level still at 8-9ppm and I was just waiting for it to slowly edge it's way down so maybe I could get a swim in later this week. I also vacuumed to waste JUST TO MAKE EXTRA SURE everything was gone.

I woke up this morning to two yellow spots (sort of near one another, and in about 2'x2' circles), but this time they look different. They aren't grayish at all (not near the stairs or in shaded areas like usual)... It's more bright yellow and almost fluorescent.

I've worked really hard at maintaining balance and keeping FC up, but I have a few questions.

#1. What FC am I looking for and for how long do I need to hold it there to actually kill all of this stuff?
#2. How do I visually tell the difference between mustard algae and pollen?

Any help here would be great. I will send pics later when I get home from work of what it looks like now.


15,000 gallon in ground pool. Sand filter.
Reading today (from Leslie's but I have my own strips and Taylor as well.. just checked with them to make sure I was getting accurate readings):

FC: 7.5
TC: 7.5
CH: 150
CYA: 60
pH: 7.8
TA: 150

Thanks in advance.
Matt
 

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