I must be missing something, assistance with chemicals pls!!

[prov431]

I have a 16x32 in ground pool, 8 ft deep, vinyl liner. 300 lb sand filter, 8 hr filter run per day on timer. (various times throughout the day) It gets full sun in North Carolina where I live. The pool gets light use, mostly my kids and myself 2 - 3 hrs daily.
I use a Taylor K-2005 kit.
My numbers are -
CYA 30
Alk 100
FC 3-4
CC 0
PH 7.2
Temp 84 F

I use liquid bleach as my chlorine, (BBB method) and typically use 32-45 ounces per day trying to keep my target value of 3-4 ppm.
Recently my water has shown some signs of cloudiness and what I believe is algae growth on the sides of the vinyl liner. I had a similar instance a few weeks ago at which time I brushed it, and used 15 ppm bleach to shock it. I believe I am doing something wrong, although I have no clue what. I would think that if my water chemistry numbers are consistantly good, then I shouldn't have any cloudiness or algae issues.

What do you think? Any feedback greatly appreciated!!!
Regards,
Dan

 

[JohnT]

Only a guess, but maybe during the middle of the day, FC is dropping enough to allow algae to get a foothold. When do you test and add chlorine? Maybe test every 4 hours some sunny day when you are home to see how it's holding????

If it was my pool, I'd be inclined to raise the CYA to 40.

 

[prov431]

I agree with raising the cya to 40, in fact I was planning on doing that.
I am also wondering, because I am fairly new at this, what is the recommended time to keep a pool at shock level?
Do you simply shock it and let it come back down, or must it be held for a pre-determined amount of time?
Again, any help appreciated!
Thanks,
Dan

Edit - I test various times during the day, mostly for experiment to see what is happening with the water.
I add bleach usually in the morning, or late evening.

 

[duraleigh]

Hi, Dan,

Welcome to the forum.

The shock process is complete when:
A. You hold FC loss to 1.0 or less overnite
B. Your CC's test .5 or less
C. Your water is sparkling

 

[prov431]

Thank you for the replies. I had just found similar information on the 'pool calculator' page hyperlinks. Good stuff right there for sure.
However, I was not able to find a definition of "mustard algae" or "black algae", and what the differences were in both composition and treatment. Can you offer anything on that?

BTW- I am just outside of Rockingham, NC. I travel to Raleigh often for work.

 

[HarryH3]

I add bleach usually in the morning, or late evening.

Add it in the evening. Sunlight quickly degrades chlorine, so by adding it in the morning you limit how much time it has to work its magic.