Can this be mustard algae?

[kcpool]

Seeing what appears to be a yellowish buildup on the side walls of my pool. Not sure what it can be...hoping it is not mustard algae. I had something similar a few days before I closed my pool last September but I vacuumed it up and closed the pool. Opened the pool early May and have had no hint of this at all until the past week. I vacuumed it the first time I saw it and shocked the pool and then a few days later it came back and I vacuum it again and it slowly accumulates again. It is showing up generally in the same area of the pool. I have high CYA that I didn't want to fix yet since we have been using the pool frequently so I have been keeping my FC high and it has been steady so that's my only hope as far as this not being algae. Anyone have any ideas? Can it just be pollen? Is that even a possibility in August in the New Jersey area?

FC - 8.0
TC - 8.0
Alkalinity- 85
PH - 7.6
CYA - 80

 

[karmabiker]

Did you SLAM your pool or do a 1 time add of shock (the product)?

 

[Butterfly]

You can do an OCLT and rule out/in organics. http://www.troublefreepool.com/content/136-perform-the-overnight-fc-chlorine-loss-test-oclt

 

[zea3]

Has your chlorine dropped below 6 ppm at any time lately? Your CYA is high so your recommended FC range is 6-11 ppm.

 

[kcpool]

It was just a normal shock...I did not SLAM. My chlorine has not dropped below 6ppm. Looks like this is going to be a little tougher than I hoped.