Which should be done first?

[mcase]

Readings today:
FC 3
CC 0
TC 3
ph 7.8
TA 150
CYA 90

I am finally getting around to working with the pool water balance. I know I need to keep the TC 7 - 10. Momentary lapse, I'll do better. Historically I had used Trichlor Tabs, until if discovered the BBB method. Both TA and CYA are elevated, so does it matter which I do first? Does lowering the water level and refilling to lower the CYA have any impact on the TA?

 

[PaulR]

Does lowering the water level and refilling to lower the CYA have any impact on the TA?

That depends on the TA of your fill water. It works for CYA because the fill water will certainly have zero CYA.

But, since you have to replace water to lower the CYA anyhow, you just do that first and then retest to see where you are with pH and TA. Fixing up the TA first is just a waste of chems.
--paulr

 

[ideliver]

If you are not having chlorine problems...you may consider leaving the CYA alone...just be aware of where your "shock" and minimum chlorine levels are...and dose accordingly

Since your pH is also 7.8...I would lower the pH to 7.2 (but no lower) and let it creep up with your bleach addition...your areation should increase with pool use now that we are getting into the summer and this will raise your pH also...


EDIT.. FIXED....my original edit needed proofed as I failed to delete the end of the sentence...the concept that I was trying to convey to the OP was that there will be two forces that will tend to increase the pH...the addition of bleach and the areation...so I would suggest targeting the lower range of the pH as it tend to drift upward....

 

[Butterfly]

Since your pH is also 7.8...I would lower the pH to 7.2 (but no lower) and let it creep up with your bleach addition...your areation should increase with pool use now that we are getting into the summer and this will help lower your TA...

Ah, aeration raises pH. Muriatic Acid lowers TA and pH. (more details in Pool School)

 

[PaulR]

If you are not having chlorine problems...you may consider leaving the CYA alone...just be aware of where your "shock" and minimum chlorine levels are...and dose accordingly

Even in Texas, CYA 90 seems a bit much for a bleach pool.
--paulr

 

[ideliver]

If you are not having chlorine problems...you may consider leaving the CYA alone...just be aware of where your "shock" and minimum chlorine levels are...and dose accordingly

Even in Texas, CYA 90 seems a bit much for a bleach pool.
--paulr

...as long as he is aware of the risks...and is aware of the FC/CYA chart..