Dirt or Algae?

[PearlandPool]

I've searched this forum but couldn't come to any conclusions on the following. My pool has accumulated some dirt like debris in certain areas. They brush away easily but eventually return in the same spots. This debris is more concentrated by the return jets so part of me thinks this may be a filtration issue. Another part of me, however, thinks this may be a yellow/mustard algae issue. Right not I'm trying to decide whether to open up the filter housing to look for any cracks or issues that would allow debris to get pack into the pool or shock the pool to mustard algae levels. I have attached pictures. My numbers are as follows. Any thoughts and suggestions would be much appreciated. Thanks.

FC: 9
CC: 0
pH: 7.8
TA: 70
CH: 340
CYA: 70
Temp:76F

 

[woodyp]

All I can say is that it's been a WICKED pollen season in Texas. I did the "mustard algae" shock thing back in the day before I wised up. I would only suspect mustard if it's in the shady areas of the pool only. And that mostly look like plain old dirt to me.

 

[jblizzle]

Well, that is either dirt/pollen or dead algae ... certainly does not look living.

I would suggest that you Perform the Overnight Chlorine Loss Test as see what that tells you.

 

[PearlandPool]

Thanks for the responses. I'll do the OCLT tonight and tomorrow morning and see how it goes.

 

[Casey]

Looks like dirt but the OCLT will surely rat it out if it's algae!

 

[Smykowski]

Any algae hiding on a solar cover?

 

[PearlandPool]

Thanks to the suggestions and comments, I'm now pretty convinced it is dirt/pollen. The OCLT test results did not budge and remained the same at both checks. So it's either wind blown debris or filter issue. I may put a clean white sock on one of the returns to see if there is any dirt accumulation before thinking about checking inside of filter housing.

I have no solar covers so can't check there, but OCLT seemed pretty convincing.