Whats wrong with pool math?

[whataboy]

TA was at 70 and set goal at 80 on Pool Math. Added the 1 pound 12 ounces of baking soda Pool Math said to add with pump and APC running tested an hour later now I got TA of 120. What's up with that?

 

[Texas Splash]

I checked the calculator on my end and also got 1 lb 12 oz for your 12K pool.

 

[whataboy]

Yeah it raised it 50ppm instead of 10ppm. Next time I will only add one third and see what I get. This is only the second time I had to add baking soda to raise TA this summer.

 

[Agent99]

I recently added baking soda for my 25k pool with the intention of raising the TA from 70 to 90.

I added just a bit under 3 quarts of baking soda going with the volume scale.

My reading came back at 100 so close enough but I did expect 90.

 

[whataboy]

I recently added baking soda for my 25k pool with the intention of raising the TA from 70 to 90.

I added just a bit under 3 quarts of baking soda going with the volume scale.

My reading came back at 100 so close enough but I did expect 90.

Yeah, I weigh mine with a very precise scale. Ozeri Microban scale from walmart

 

[chem geek]

I would double check your TA test and make sure that you don't have static electricity on the dropper tip that is squirting drops instead of having well-formed hanging drops. Wipe the dropper tip with a damp cloth first. There's no way that 1 pound 12 ounces of baking soda (about 2.8 cups) added to 12,000 gallons increased TA by 50 ppm. The PoolMath calculation is right. Something else is wrong at your end -- the TA test, the pool size, or the amount of baking soda actually added.

Also, if you tested too soon in the area you added it, then you could be measuring a locally high TA area and instead need to wait 30 minutes with good pool circulation before measuring.