Another Newbie Chem question

[jfhaas]

Glad I found this site!

I'm a new pool owner, and have been having problems keeping my CYA at 70 - 80 ppm, and my pH below 8.0. About a week ago, I added granulated CYA in an attempt to raise CYA from 60 to 70 ppm. Yesterday, I added acid to lower pH from 8.0 to 7.4. It's been about a week since I added stabilizer, and my Taylor test readings are as follows:

CYA = 60
pH = 7.8
Total Alk = 100
Ca hardness = 275
Free CL = 4
Combined Cl = 0
Water tem = 84

With the addition of CYA, I expected CYA to increase, Alk to decrease, and my pH to stabilize.

What am I doing wrong? Is it possible the aeration from my spa waterfall is effecting my chems? I understand my Ca hardness is low, but wanted to take care of the CYA/ pH problem first.

Thanks,

 

[Dz7]

Have you gotten a lot of rain since you added the CYA? How did you add it? pH in salt water pools tends to rise incessantly until you hit a certain alkalinity level. I test hundreds of pools a week being in the industry and one thing I've noticed is that when the alkalinity hits around the 70 range roughly, although I've noticed lower thresholds, the pH rise will slow dramatically and stay more stable. Also, the aeration from the water feature can affect your pH, and the rain aerates the water as well. Aeration raises pH if I'm not mistaken. If I'm wrong somebody chime in. Oh by the way, the chemistry looks great from what you posted. Chl/CYA ratio is met almost perfectly.

 

[robertmee]

Yes....to reinforce what Dz7 says, get your alkalinity down to about 60 or 70. I too have an SWG and waterfalls/ribbons, and my pH even with aeration stays pretty rock solid between 7.5 and 7.8. But it took lowering my alkalinity to 70 to achieve.

As for your CYA, granulated stabilizer can take a week or more to fully dissolve and test appropriately. If you've not had any rain or water exchange due to splashout/refill, then wait another week and test again before adding any more stabilizer. It's better to be cautious when adding.

 

[Divin Dave]

You aren't doing anything wrong, except perhaps expecting too much from the addition of a few lbs of CYA.
Your spa waterfall will definitely effect the pH rise.

Adding CYA will knock down the pH a little and the TA very little. Not enough to be very noticeable though.

 

[jfhaas]

Thanks for the response!

A lot of rain - yes
Added CYA - granulated, directly through the skimmer (I learned later to use a sock)

I'm pretty sure the water feature/ is not helping the situation. Unfortunately, there is no way for me to isolate the spa/ waterfall.

- - - Updated - - -

Thanks again for the replies.

Also, I was reading that adding borates would help mitigate the swing in the pH which I believe is caused by the spa waterfall/ aeration. It seems like I'm adding acid daily just to ge the pH down to 7.6

 

[Piolin]

Have you contemplate adding borax, my TA is 70-80 and with borax my pH stay at 7.8 all the time

 

[Schadenfreude]

My advice: get your TA down before you add borates. After you add them, it will be much harder to get the TA down if you need to.

You may find that your Ph stabilizes when you lower TA to 60 or 70.

Remember to pay attention to your CSI, though.