Okay... TA was at 80, now at 60. 225oz of baking s?

[Motor]

Heya! Pool was solid at about 85 TA for a while, now it's at 60 two days later after adding a gallon of chlorine and 1/8 gallon MA.

30k gal, plaster, 50deg water, copper pipes.

TF test kit

Chlorine (10%) 7ppm
Cya 50
TA 60
Ph 7.65

It says in the pool calculator to add 225oz of baking soda to ramp it up to 100, from 60. That seems like a lot of baking soda. Really? That much? :/

Love this site! Thanks everyone!

 

[Richard320]

Depending on the CH level, 60 TA might be a good target. It is for me, because I have really hard water.

I also think there might be a testing error somewhere, because 2 cups of acid in a 30K pool shouldn't affect TA that much.

 

[Motor]

I know. Maybe it was testing high before? When I read 60, I retested 3 times. Yup. 60. I'll test CH and report back in a few mins. Thx!

 

[Motor]

CH is 320 when the color starts to change, but it's REALLY blue at 380 and stops getting bluer. Not sure how t read it.

 

[JamesW]

CH is 320 when the color starts to change, but it's REALLY blue at 380 and stops getting bluer. Not sure how t read it.

Most likely a result of copper ion interference.

The sample may turn purple during the test, or go to blue for a moment and then turn back to red/pink. This is called a "fading endpoint" and is caused by interference from metal ions. If this happens, do the test again, but this time add five drops of R-0012 before adding any R-0010 or R-0011L. Remember to count the initial five drops in the total.
In extreme cases, a fading endpoint may occur even when adding five drops of R-0012 at the start. If that happens, mix pool water with an equal quantity of distilled water, test that, and then multiply the result by two.
extended-test-kit-directions-t25081.html

I would recommend maintaining a pH closer to 7.7 or 7.8 and a TA of 60 to 80 depending on where the pH maintains the recommended range without drift..

 

[Motor]

Cool thanks. The Water is old... although at Leslies tested Zero for metals.. I know those tests arent the best for testing low quantities of metal, but I'm aware sometimes even low quantities can affect results in other tests.
I'll try the tricks you quoted here. I added just a box and a half of Soda to bring it up slightly, but I figured keeping it around 80 is probably okay.

Why do Salt pools require lower TA?

Just out of curiosity, what chemicals do pools stores sell to raise TA, like I am with the Soda?

 

[UN1017]

Why do Salt pools require lower TA?

During the process of making chlorine, SWGs cause pH to rise. By reducing your TA, it can help stabilize that rise and reduce the frequency of adding acid.

Just out of curiosity, what chemicals do pools stores sell to raise TA, like I am with the Soda?

They are usually labelled Alkalinity Up, Alkalinity Plus or something similar. Silly though...it's just baking soda and you'll pay a premium for it.

 

[Motor]

So SWGs cause the Ph to rise more than liquid chlorine? Or is it just that since it's running 24/7 it seems to make the Ph rise more? If this is the case, what's the downside of keeping the TA around 60-80 for all pools?

Is this the reason that Salt water pools aren't as drying on people's skin? Or is this just the salt conditioning the skin?

 

[Bama Rambler]

People tend to put too much emphasis on TA being a certain number. As long as it stays above 50 ppm, just let it work itself out.

What tends to happen is that by adjusting the pH whenever it needs it, the TA will also be adjusted and will find it's happy place where the pH doesn't rise, or at least rises slowly. However, some SWG installations, for unexplained reasons, don't follow this rule and the pH keeps rising to where by constantly adjusting it down the TA actually gets too low. In those special cases, one just needs to keep the TA at about 50 ppm.

The reason that a swg pool isn't as drying on the skin is because the salt level in the pool is higher than normal and therefore is closer to the salt level in the body.

 

[Motor]

Alright! Thanks for the info.