Algae? PH drifts up... CYA falls...

[sdaggie]

I've had an odd summer when it comes to my pool chemistry. I've battled what I think is an algae problem all summer - I have the brownish residue that disappears when swept (see pic). I brought it up to SLAM levels several times and passed the test but I continue to battle the brown residue and the following issues:

- PH drifts up every week - I use muriatic to lower it.
- Combined chlorine always stays at .5 - have not been able to get to 0 all summer.
- In past summers, CYA ran high. This summer it keeps dropping - I've had to add stabilizer twice.
- I think a lateral in my filter might be broken - I see a small amount of sand in front of the jets.

My numbers:
FC 4.5
CC .5
PH 7.6
CYA 40
TA 90

Are these issues related in any way? I'm replacing my liner next year so I don't know if I should just maintain or keep looking for the algae source? Also, water is crystal clear! TIA!!

 

[ajw22]

How do you chlorinate your pool?

Target FC for CYA 40 is 5-7. Running at 4.5 is too low. Run your FC at 7-9.

What is your pool water temperature?

pH drifting up is what some pools do.

What is the pH and TA of your fill water?

 

[sdaggie]

Chlorinate pool with liquid 12.5% Sodium Hypochlorite.

Interestingly, I was using a chart I printed off when I started BBB in 2014 that shows a target FC level of 5 for CYA 40. I will now use the newer chart and raise my levels.

Temp is 88 today. The cover is on when not in use which probably warms it up.

Fill water TA 130 and PH 8.0+ (very red). I did just add about 2 inches on Monday.

Thank you!

 

[ajw22]

Temp is 88 today. The cover is on when not in use which probably warms it up.

CYA degrades as the water gets warmer. Read CYA - How_is_CYA_Lost_and_Degrade_in_Pool_Water?

Fill water TA 130 and PH 8.0+ (very red). I did just add about 2 inches on Monday.

That fill water pH and TA contributes to your pH rise.