fighting mustard algae

[Kateyru]

Hi Guys, I'm back home and pool looks good...not visible algae but high FC may be compensating. So, here are current results:
FC = 10.5
pH = 7.7
CYA = 50
TA = 90
I know that CYA needs to be higher. Do I lower pH and TA first or raise CYA?
SWG was running at 65% so have turned it down to 35% to lower FC. In the past, running it at 50% has kept FC steady.
Thanks!!!!

[aylad]

Leave pH and TA alone and add CYA.

Janet

[Kateyru]

Thanks so much!
Happy 4th!!!!!!!!!!

[BigDave]

I wouldn't drop the pH just yet, let it get closer to 8.0. When you do lower it, bring it down to 7.5/7.6. This will drop your TA. When the SWCG brings it back near 8.0, lower it again. You will be performing the TA reducing procedure but slowly.

Go ahead and bring up the CYA and good luck with the yellow algae.

[aylad]

Uhh, I just said that!!

Janet

[BigDave]

Yep, sorry. Me post real slow. OTOH I'm glad we're saying the same thing

[Kateyru]

Hi again,
I added CYA on 7/6. FC = 8 on 7/6 at 6:30 am and FC = 7 this morning and SWG has been off since yesterday morning. Slow drop with sufficient CYA, huh?
My pH = 7.7 today. I'm trying to let FC drift down to 5. Should I work on pH yet?
Mustard algae is still gone...yea!!!
Thank you, thank you!!

[aylad]

I wouldn't drop the pH just yet, let it get closer to 8.0. When you do lower it, bring it down to 7.5/7.6. This will drop your TA. When the SWCG brings it back near 8.0, lower it again. You will be performing the TA reducing procedure but slowly.

.

[Kateyru]

Hi Team,
I'm back again...after being gone for 3 weeks. A 2-week vacation, 1 week at home and another 3-week vacation is great for me but not so good for the pool.

test results on 7/4 were as follows:

FC = 10.5
pH = 7.7
CYA = 50
TA = 90
I added stabilizer before I left town trying to get level to 70. I asked husband to check FC and pH daily and to let me know if FC got to 5 and when pH got to 7.8 so he could add acid to lower and get TA down. He says that he checked every few days and FC never got down to 5 and pH never got up to 7.8. He only added salt while I was gone. We had lots of rain and high temps of 100 for many days.

Test results yesterday:
FC = 8
pH = 8
TA = 48
CYA = 60 to 70
and, natch, I have algae again.

I am now shocking again (at 20 since CYA is 60-70).

What made TA go down like that...rain, debris in pool????

FC stayed high (somewhere between 7 and 8) so what made algae return? pH too high?

After I shock, what is next step? Raise TA? Raise CYA?

Thanks.

[BigDave]

Mustard algae? I don't think you ever killed it all. You'll need to take the FC way higher than 20 and keep it there for a long time and brush everywhere it might hide. Please don't raise your CYA at this point.