Water balance testing

[TXRon]

Using TF-100 and salt strips I got the following numbers a few days ago
PH 7.8
FC 5
CC 0
TA 90
CH 310
CYA 80
Salt 3550

Pool store results from today.
FC 3.4
ph 8.0
Alkalinity (w stabilizer correction) 26
CYA 80
Salt 3000

Pool store recommends adding 38 pounds of baking soda because alkalinity level is low (26). Recommended range is 80-120. But own test results for TA is 90.

Do I add or not add the baking soda? And if I do add it, won't that cause my TA to go up even higher?

Thanks,
Ron

 

[JasonLion]

Welcome to TFP!

You should trust your own test results over what the pool store says. If there is any doubt, do the test again yourself. There is no point in adding baking soda unless your own test results show a number down around the one the pool store got. Pool store test results are wrong a surprisingly high fraction of the time. Also, you never want to use the stabilizer correction when deciding if your should raise TA. The "corrected" number is only used for calculating LSI (which most people can completely ignore).

By the by, with a SWG, we recommend TA be between 60 and 80.

 

[TXRon]

Thanks Jason!

That's what I thought but wanted to make sure.

It hasn't been easy keeping the TA level in 60-80 range. As soon as I get it there it creeps back up. It must be due to the fill water. Not having any water features to aerate doesn't help much either.

And thanks for all the helpful advice on TFP and BBB method! It just works.

Ron

 

[UnderWaterVanya]

Measure your fill water and report back the results...

Sent via Tapatalk...

 

[TXRon]

Tested the fill water.

TA 170

So, that is indeed the source of the increasing TA level.

Ron

 

[UnderWaterVanya]

Tested the fill water.

TA 170

So, that is indeed the source of the increasing TA level.

Ron

Yup. Lots of acid use in your future to keep the levels down. You can try using rain water as another source for fill water.

Sent via Tapatalk...

 

[duraleigh]

Just for clarification, do not plan on using just acid to lower your TA. Your pH will be driven down to unacceptable levels.

As you likely already know, TA must be lowered using the aeration/acid process outlined in Pool School. :lol:

 

[TXRon]

Per pool calculator, added enough MA to drop ph to 7.2 as well as brushed the walls/floor. Turned the returns up with pump on high to aerate and will continue to do so until ph comes back up.

Lather, rinse, repeat.

Ron

 

[TXRon]

Right now it takes around 24 hours, running the pump on high speed with returns facing up, to bring ph up from 7.2 to 7.5. I also want to add borates to the pool this spring for reasons other than keeping ph from rising as fast.

Given:
My fill water has high alkalinity (rising TA)
I have a SWG (rising ph)
I need to add MA to decrease ph to 7.2 and lower TA, then aerate at least 24 hours to raise ph back up to acceptable range

When:
I add borates

Then:
Would I expect to have to aerate longer?

Ron

 

[duraleigh]

I am not so sure that you will need to aerate as much as you might think.

I would first control the assumed rising pH with muriatic and then monitor the TA. If TA stays somewhat reasonable (say 120 or so) AND your pH does not require CONSTANT muriatic to keep it in the 7's, then there is no need to aerate.

I don't personally use borates but I don't think that will make very much difference, if any, in your aeration process.