Yellow mustard algae

[LuLu]

What is the difference between green algae and yellow mustard algae? Also can pollen mimic algae? The reason I ask is that I have been battling algae the past two weeks.

My numbers:

Ch 15
CC 0
TC 15
TA 130
Cal 280
CYA 45
I have shocked to 15 ppm and kept it up until chlorine held overnight. Water is clear but when I brush it in the afternoon I see what appears to be a fine film of algae after I push the brush across the bottom. I am just wondering if I am not shoicking high enough or if the chlorine is dipping mid-day. There is no sign of algae in the mornings when I brush. How high can I safely shock the pool- it has a vinyl liner?

 

[frustratedpoolmom]

15 is fine....if it held over night and you have no cc's that's not algea. It could just be pollen dust or dead algea. Have you tried letting it settle and vacuming it out?

 

[JasonLion]

Green algae usually floats in the water and turns the entire pool a murky green. Mustard algae is a yellow green color and grows on the walls and floor mostly on the shady side of the pool. Pollen and dirt tends to accumulate in drifts on the floor in places with slower circulation and can often look fairly similar to mustard algae. There are occasional exceptions to all of these rules, green algae sometimes grows in mats on the walls or floor, mustard algae sometimes floats in the water, etc. So positive identification isn't always easy.

 

[LuLu]

Thanks for the replies. This stuff is so fine that it is hard to vac. It has been so dry around here this summer that it may be a fine dust/pollen that settles and my sand filter isn't filtering. I am going to get some skimmmer socks for the basket and some DE to add to the filter. Another question, my TA is 130 and I want to add borates to my pool. Should I lower the TA? Also I've continued to keep the chlorine at 15ppm. Do I need to let it drop before adding borax and acid since high chlorine affects PH? My pool is 4 years old and we used baqua-Crud the first two years and last year I converted it to chlorine. Can I assume that the borates are 0 or should I test before adding?