TA too low. Baking Soda not increasing it. Please help.

[Tatum4701]

I've got a 200 gallon spa. My pH and TA were both very high. I've finally gotten the pH down to 7.6 with muriatic acid, but now my TA has fallen from 40, down to 20. I had been adding baking soda to try to get it up to 50.

Is there something else that will bring TA up? Does the age of the baking soda matter? Should I do it more frequently? What is the trick to getting TA up and pH down?

 

[Mdragger88]

The ta shouldn’t have fallen that low if you were not reducing ph below the 7’s.
I assume you added to much acid.
I don’t believe the age of the baking soda should matter too much.
Ta of 40 or lower can make ph bounce around- so until u get ta to 50 - don’t worry adjust ph.
Add the amount poolmath says to get to 50 again Which looks to me like about 3 tablespoons.
let it circulate about 20 min & test ta again

 

[Tatum4701]

I added 3 tablespoons of baking soda. I thought I had to wait 2 or 3 hours to wait for it to work before testing again. I'll test again now and see if my TA has improved. I'm just on day 3 with figuring this out. I can't wait until I do, and it gets easier! Thank you.

 

[Mdragger88]

Also before you adjust ph let the tub “rest” 20 min or so before u test.
If u have been running the jets the ph will increase while in use but it will settle to its real ph after they are off a bit.
*update your signature w/ your tub info so you can get the appropriate help quickly

 

[wayner]

I have a pool and a spa and I always struggle to balance pH and TA in my spa. My pool is rock steady, but the spa is a neverending battle. Whenever I add baking soda it increases my pH. So I have to add more acid which reduces my TA. Rinse and repeat.

 

[Tatum4701]

From TA 20, I must have lost count when adding baking soda, because it shot up to TA 130! More muriatic acid, and I got the TA to 60 and pH to super yellow. Lol. 6.4?? I've aerated for a few hours. TA still at 60, and pH at 7.0 now. I'm hoping a bit more aeration, and I'll get to pH 7.5 and TA 50.

 

[jseyfert3]

The key is SMALL additions. I find a gram scale very useful when adding small amounts of dry chemicals in my tub.

Run all pumps on high after chemical additions to quickly and completely mix all chemicals.

And when adding acid at low TA levels (like 50), very, VERY small amounts! For instance, to go from 8 to 7.6 in my 450 gallon spa at a TA of 50 takes...0.2 oz, or ONE TEASPOON of 32% (20° baume) muriatic acid. And always make sure PoolMath has your current TA level before calculating acid additions.

Always be very accurate and slow when adjusting pH and TA in a tub at a TA near 50. Low pH (<7) can damage the metal heater in your spa and should be avoided.

 

[jseyfert3]

Honestly, I find it difficult to pour an amount of liquid acid that small. I'm thinking of switching to dry acid going forward after I knock my tap water from 350 to 50 ppm TA (large amounts of sulfates from dry acid can damage heaters over time from what I've read, otherwise I would have been using dry acid already). The same drop in pH from 8 to 7.6 in my spa is 0.3 oz of dry acid, which is easy to accurately measure with a gram scale, unlike a teaspoon of fuming liquid acid.

 

[Mdragger88]

@Tatum4701 be sure you have the correct water volume for your tub. Also i use this to measure additions along with google conversions from oz to tsp.

I also have a 200 gal tub.
aerate to increase ph. Changes happen more quickly in a small tub than a pool.

 

[Mdragger88]

Also just do 1/2 amount additions & see where that gets u from here on out - especially with acid. It should help u dial in your real gallon volume. use poolmath effects of adding to dial it in .
Aeration should get u to the right ph .

 

[jseyfert3]

Also i use this to measure additions along with google conversions from oz to tsp.

Where did you get that?

I use the 8 oz version of this for measuring chlorine and acid (I have one for each). It works well when you need to add close to an oz or more, but for super tiny amounts like acid when TA is near 50 it's not great. (I use the 64 oz versions for my 15k gallon pool)

 

[Mdragger88]

Dollar bin @ the Walmart
-

i use a glass mason jar for bleach additions because it has marks every 2oz & it fits in my bucket under the table on the patio.
For the pool i have a $1 plastic measuring cup & a $1 gallon pitcher that i marked the quarts - I don’t have to make many additions to the pool. I have had the same 2 ma bottles for over 2 years.