PH or CYA

[nthoms]

I recently opened my pool. I have little to no FC/CC despite adding both liquid and granular shock .

My PH is below 6.8 and my CYA is reading little to none.

Which should raise first? PH or CYA? Or does it even matter? Or is there a different approach I should take.

Water is clear and looks fine.

Thank you.

 

[mknauss]

What is your TA?
Please post a full set of water chemistry test results.
Please add what test kit you use to your signature.

 

[nthoms]

FC: .2
CC: .4
PH: <7.0
TA: 50
CH: 130
CYA: <10
SALT: 2200
68°

 

[mknauss]

Add chlorine. 3ppm FC worth
Add baking soda to raise the TA to 70 or 80 ppm.
Add CYA to get to 30 ppm using the sock method.

 

[nthoms]

Still no chlorine registering. What am I doing wrong? Pool water is crystal clear. But registering no chlorine.

FC: 0
CC: 0
PH: 7.4
TA: 80
CH: 130
CYA: 30
SALT: 2800
71°

 

[Oly]

Are you adding liquid chlorine with the pump running and testing after 30 minutes? Don't rely on your SWCG system now you need to source liquid chlorine without additives. You may have a building algae bloom that has not gone green yet and you can diagnose this with an Overnight Chlorine Loss Test. Also read through the SLAM Process to control algae.
The SWCG system is great for maintaing FC but will not keep up once algae is established.

 

[nthoms]

I added 2 gallons of liquid chlorine yesterday afternoon ... took a measurement this morning and got a FC reading of 2. So that's a good sign ... right? Can I add use chlorine granules? ... I don't have anymore liquid chlorine.

 

[Oly]

If you use solid forms of chlorine you will be adding either calcium or CYA along with the free chlorine FC and also may be dropping your pH, so know before you throw. Use pool Math to estimate how you are altering your water chemistry. Sourcing additional liquid chlorine for a SLAM and keeping some in stock to boost FC immediatly is the best practice.

 

[nthoms]

Would you be able to help me understand if my "solid" chlorine has the other stuff in it? I use CHLOR BRITE which says 99% "sodium dichloro-s-triazinetrione dihydrate" and 1% other. So does that mean it also has the other non-chlorine stuff?

 

[Oly]

Sure, use Pool Math with this link..... PoolMath

Enter your pool size in gallons, 22,500 at top left.
Skip down to the bottom look for effects of adding chemicals.
Enter 16 oz of dichlor (use drop down menu) and you will see the estimated result. Raise FC by 3ppm, raise CYA by 2.7ppm, lower pH by .11 and raise salt by 2.4pp.
By entering more data and setting up your system details you can also use the FC and pH component to estimate amounts of chemicals to reach target levels in your water but wait until you have your test kit before going much further as too much of some products require draining.

Chlorine is a gas, to use it as a solid it is combined with CYA to form dichlor or trichlor, Cal-hypo is combined with calcium and to use it as a liquid it's combined with water.

 

[cznkane]

https://www.phta.org/pub/?id=08FA1535-1866-DAAC-99FB-F5E639FBE1C0

"Use provides cyanuric acid, which stabilizes free chlorine"