Need to lower TA and raise CYA a bit

[minxcal]

Hello!

I've been working on lowering TA since pool was installed. Backwashed yesterday which meant I needed to add even more water than I already needed to add, so added some yesterday, and then it rained and it came back up from 120. Trying to hit the target!

Current readings:
FC - 4
CC - 0
pH - between 7.5 - 7.8, so go w/ 7.6
TA - 140
CYA - 40

With all of that yesterday, with today's test, TA crept up 20, and with the rain and the top off, CYA is down 15, pH came up since last addition of acid, so now I also need to add a bit of stabilizer. I know CYA will lower pH, but will it also lower TA? If not, should I just add the CYA, wait, and add acid for TA when it's all done and pH is back up from stabilizer addition or add acid then just wait a couple of hours and add CYA?

 

[GuinnessPhish]

CYA doesn't affect pH.

With a CYA of 40, you should be fine. Why are you trying to raise CYA?

 

[GuinnessPhish]

disregard.....sorry

you're using a SWG, so that's why you want to raise CYA to 70 - 80.

How many gallons is your pool?


Have you used the poolcalculator?:

calc.html

 

[minxcal]

According to the pool calculator, CYA lowers pH, quite a bit actually:

I have a SWG. CYA if 40 is not near enough.

 

[minxcal]

I use the pool calculator almost daily. I just need to know what order to attack things.

 

[GuinnessPhish]

According to the pool calculator, CYA lowers pH, quite a bit actually:

I have a SWG. CYA if 40 is not near enough.

Oops. Open mouth, insert foot.


Learn something new everyday.


If the CYA lowers pH, then it should also lower TA, right?

 

[minxcal]

Ha! yeah, me too! I love this forum. Studied up for about 6 weeks before I ever even posted anything cause I didn't want to be told to read Pool School - I alredy did it - many times! I think I'm going w/ adding acid, bringing pH back up, then add CYA in a sock at the end of the day. Sounds like a plan to me!

 

[Smykowski]

If the CYA lowers pH, then it should also lower TA, right?

Yes. The faster way to do it is to lower pH with MA, then aerate. However, since CYA is acidic, the same process occurs. (But pH drop is a byproduct of CYA addition. Don't lower pH with CYA exclusively!!)

 

[linen]

Adding that much cya (32 oz) will only lower your TA by about ~10 ppm (depends on a number of other things) and it will drop you ph less than the calculator shows since your TA is a little higher. In the end you might not even notice the ph drop from the cya since it dissolves slowly and your ph will be creeping up.

I would ignore the ph effects of the cya for now (assuming granular) and deal with getting your TA down independently.