Yellow Algae

[cood60]

I keep vacilating on what to do about a yellow "film/dust" that accumulates on seams and creases, mostly on the opposite side of the returns.
I was going to do yellow algae shock ie 40ppm shock
But the overnight FC Loss test showed under 1 as FC loss, CC was at .5 or lower, and water was clear, so I am not sure what the yellow stuff is.
The yellow dust has multplied over night so I need to nip it The water is still fairly clear unless I brush the yellow stuff. But the yellow stuff is all over the bottom though thicker is some places

Here are my levels
FC 8 (I got scared because my fc dropped to 1.5 so I added bleach)
CC .5
TC 8.5
ph 7.6
CYA 60 Had dropped to 30 a few days ago so I raised it. I added raise fc to 8 at that time because it had dropped to 1.5 over night
TA 70 (pool store says it is 100!)
CH 140
Salt 2700
Phosphate 600 (according to pool store, I do not have that test)

Pool store says 40 ppm will fade my liner and say I should use 30ppm then add Banish Agecide thew next day
I am wondering if I go ahead and do the Algecide, will it hurt anything or cause any additional issues? Like having to use it the rest of my life

How long does it take for the 40+ ppm to reduce to 5ppm?

What is the highest ppm of chlorine allowable to swim in?

Will 40ppm fade my liner?

Is there any downside to using an algecide instead? ie will using that mean I have to keep using it from now on?

If I do the high chlorine shock treatment, this is my current understanding of the method with some questions:

Vac to waste
Reduce Ph to 7.2
remove lights and ladder and skimmer doors
Raise FC to 40ppm, my CYA is 60-70 (I just raised it as it had fallen to around 30)
Should I keep pump running on high the entire time?
Put all the pool toys and tools and swimwear in the pool
How long should the FC be above the min level (5 for me)
How long does it take for the FC levels to be reduced to normal
Some say the Fc should never be abobe 4 ppm for swimming?
Should the SWG be off during this treatment?
Thanks for advice

 

[duraleigh]

Wow! I can't answer all those questions but I will say if it was my pool I would simply read "How to Shock Your Pool" up in Pool School and follow that PRECISELY.

You are blending advice from the pool store with advice from the forum and they seldom match and you end up in the middle.

I see no reason to shock your pool so high since I can't find anything in your post that says you have shocked it correctly yet.

Shock is a process that requires you to maintain shock value (20ppm) for a period of days until your pool is crystal clear. Read that article and you'll be on your way.

 

[cood60]

Thanks. I did read and re-read all the shocking articles. The reason for the 35-40ppm is because the that is what the pool school recommends for Yellow Algae shocking as per the CYA chart and or 60% of CYA ie a CYA of 60 would require 36ppm, 70 would require 42. I added some water to help dilute (and prepare for vac to waste, hoefully will lower cya a bit

Thanks for the quick reply

 

[duraleigh]

I think you may still have missed the part about holding and constantly replenishing the FC at shock value until the pool is crystal clear.

Going to 40ppm and following the process for mustard algae is fine if you want to do that I do not believe it's necessary in your case) but it will still require that you HOLD the FC at 40 for perhaps days....not a one time dose.

 

[chem geek]

Don't forget the part about getting behind light niches and under removable ladders, if applicable. If the area where the yellow dust is settling isn't the shady side of the pool, then it's probably not yellow/mustard algae -- it really doesn't like direct sunlight.

 

[cood60]

Thanks to Dave and Chem Geek
Have removed ladder and lights and cleaned, am in the middle of it now
Interesting about the mustard algae not likely growing on the direct sunlight side ...it is both sides and I hope it is not mustard...now that there is more of it, it does seem to have a green tint to it.
So that should take a normal shock amount, right?

 

[Bama Rambler]

You can certainly shock if you want, but if you passed the OCLT and your water is clear except for the dust I'd believe it isn't algae. Can you pick up some of it and rub it between your fingers? If it's algae, it'll be slimy. Then rub some of it on a white paper.

 

[Mona]

I'm curious as to how your CYA dropped to 30? Did you remove half of your water? CYA doesn't disipate, the only way to get rid of it is to remove water.

 

[cood60]

No, not half but maybe 12" as it rained torrentially the last month or so, I am baffled by the loss, esopecially since I raised it to 70 and then 3 weeks later it is 50 without any water removal. I will be paying a lot more attention to CYA levels and aslo how much water I add. I have to rebalance soon as I am in the middle of the famous algae shock process. The folks on this site have been so helpful and ecouraging.