Puzzling pool deposits

[mchaos]

Hello all,

I have been battling for the past couple of weeks these green-yellow looking deposits in my pool (see attached picture). We have had quite a bit of rain lately and I initially thought that these were probably due to dust/pollen accumulated on the pool screen enclosure and carried into the pool by the rain. However, we have not had any serious rain for the past several days and these deposits reappear even though I brush and/or vacuum every couple of days. My current chemistry levels are:

FC - 4.6 ppm
CC - 0.0 ppm
pH - 7.8 ppm
TA - 70 ppm
CYA - 60 ppm
CH - 310 ppm
Salt - 2900 ppm

I did an OCLT and the loss was 0.4 ppm. So, in principle, these deposits should not be some kind of algae. I am considering SLAMming nonetheless because I am paranoid. Maybe one of you has dealt with a similar situation and can enlighten me.

Thank you for your responses,
Marcos

 

[JamesW]

I would guess that it might be mustard algae, but I cannot tell for sure.

 

[mchaos]

I would guess that it might be mustard algae, but I cannot tell for sure.

Thank you for your response.

I started the SLAM process about 4 hours ago. As soon as I dropped all the liquid chlorine needed to raise the FC to SLAM levels, the water turned all kinds of cloudy. So, I guess I am dealing with mustard algae indeed. We will see how it goes; first time doing this ...

Cheers,
Marcos