TA and pH (new hot tub owner)

Jump to latest Follow Reply
jseyfert3

jseyfert3

0
Silver Supporter
Bronze Supporter
TFP Guide
Oct 20, 2017
1,973
Southern WI
Pool Size
15000
Surface
Vinyl
Chlorine
Liquid Chlorine
Hello all,

New spa owner here. Got an Intex inflatable "6 person" spa with bubble massage. I've read and am following the How do I use Chlorine in my Spa (or Pool). I haven't yet added dichlor, I'm still working on the acid and aeration portion of the guide.

Got the tub inflated Thursday and partially filled. Finished filling Friday morning with some hot water and started testing and balancing. Testing with Taylor K-2006 test kit. All aeration periods 1/2 hour as that was the auto-off length on the bubbles. oz are weight, not fl oz, weighed with a small scale.

Initial Testing:
  • Calcium hardness: 250 ppm (might have miscounted one or two drops)
  • Total alkalinity: 275 ppm
  • pH: 7.3. 3 drops acid demand dropped it to 7.0
  • 290 gallons, according to Intex

Friday:
  1. Aeration. pH now at 8.0 (max reading). Acid demand was 8 drops to 7.2, or roughly 2.5 oz 31% MA according to tables and conversion.
  2. Added 2.4 oz MA.
  3. After 1/2 hour without aeration, pH was at 7.3
  4. Aeration. pH now 8.0
  5. TA now 175-200 ppm, though I think I miscounted drops.
  6. Added 2.5 oz MA, aeration.
  7. pH 8.0. 6 drops acid test to 7.2.
  8. Added 2.5 oz MA, aeration.
  9. pH at 8.0. TA at 175 ppm (this time I know I didn't miscount)
  10. Added 3.0 oz MA, aeration.
  11. pH at 8.0.
  12. Added 3.1 oz MA, aeration.
  13. TA now at 125 ppm.
  14. Added 3.2 oz MA, aeration.
  15. Water temp at this point was 75 ****°F, I covered it and went to bed.

Today:
  1. Water temp at 88 °F. pH was 7.8 before aeration. One drop acid demand took it to 7.4, 2 drops down to 7.0. TA was at 70 ppm, this time I used the fine measurement (10 ppm/drop)
  2. Added 0.6 oz MA, aeration
  3. pH at 8.0. TA at 60 ppm.
  4. Added 0.8 oz MA, aeration.
  5. pH at 8.0. TA at 60 ppm (Colorless at 5th drop, red on 6th)
  6. Covered and let sit, came here to post. Water temp at 83 °F when I left it.

The guide implied that once you get to ~50 ppm TA, aeration would bring your pH up to ~7.6 and it wouldn't go higher. I'm almost there, and the pH is still at 8.0 or higher after aeration. I just don't want to overshoot, wanted to make sure I'm not missing anything before I add more acid. Do I need to let it sit longer between testing? For many of the tests, I would add acid, aerate, then test almost as soon as the 30 minute aeration was done.

So, my main question is: Should I continue adding a little acid to drop the TA to 50, or should I start adding borates and dichlor, adjusting pH as needed going forward? Or am I missing something here?
 
jseyfert3 said:
Hello all,

New spa owner here. Got an Intex inflatable "6 person" spa with bubble massage. I've read and am following the How do I use Chlorine in my Spa (or Pool). I haven't yet added dichlor, I'm still working on the acid and aeration portion of the guide.

Got the tub inflated Thursday and partially filled. Finished filling Friday morning with some hot water and started testing and balancing. Testing with Taylor K-2006 test kit. All aeration periods 1/2 hour as that was the auto-off length on the bubbles. oz are weight, not fl oz, weighed with a small scale.

Initial Testing:
  • Calcium hardness: 250 ppm (might have miscounted one or two drops)
  • Total alkalinity: 275 ppm
  • pH: 7.3. 3 drops acid demand dropped it to 7.0
  • 290 gallons, according to Intex

Friday:
  1. Aeration. pH now at 8.0 (max reading). Acid demand was 8 drops to 7.2, or roughly 2.5 oz 31% MA according to tables and conversion.
  2. Added 2.4 oz MA.
  3. After 1/2 hour without aeration, pH was at 7.3
  4. Aeration. pH now 8.0
  5. TA now 175-200 ppm, though I think I miscounted drops.
  6. Added 2.5 oz MA, aeration.
  7. pH 8.0. 6 drops acid test to 7.2.
  8. Added 2.5 oz MA, aeration.
  9. pH at 8.0. TA at 175 ppm (this time I know I didn't miscount)
  10. Added 3.0 oz MA, aeration.
  11. pH at 8.0.
  12. Added 3.1 oz MA, aeration.
  13. TA now at 125 ppm.
  14. Added 3.2 oz MA, aeration.
  15. Water temp at this point was 75 ****°F, I covered it and went to bed.

Today:
  1. Water temp at 88 °F. pH was 7.8 before aeration. One drop acid demand took it to 7.4, 2 drops down to 7.0. TA was at 70 ppm, this time I used the fine measurement (10 ppm/drop)
  2. Added 0.6 oz MA, aeration
  3. pH at 8.0. TA at 60 ppm.
  4. Added 0.8 oz MA, aeration.
  5. pH at 8.0. TA at 60 ppm (Colorless at 5th drop, red on 6th)
  6. Covered and let sit, came here to post. Water temp at 83 °F when I left it.

The guide implied that once you get to ~50 ppm TA, aeration would bring your pH up to ~7.6 and it wouldn't go higher. I'm almost there, and the pH is still at 8.0 or higher after aeration. I just don't want to overshoot, wanted to make sure I'm not missing anything before I add more acid. Do I need to let it sit longer between testing? For many of the tests, I would add acid, aerate, then test almost as soon as the 30 minute aeration was done.

So, my main question is: Should I continue adding a little acid to drop the TA to 50, or should I start adding borates and dichlor, adjusting pH as needed going forward? Or am I missing something here?
Click to expand...
Get to a TA of 50 before you add your borates
 
Thanks. I added another 0.7 or 1.0 oz MA (didnt have my phone to note it and I forgot). TA now reading out at 40 ppm, so I may have overshot slightly. I'm aerating now, will check pH after and if it's 7.8 or lower I'm going to add the borax and acid PoolMath calls for to get to 50 ppm borates, and follow with shocking using diclor.
 
jseyfert3 said:
Thanks. I added another 0.7 or 1.0 oz MA (didnt have my phone to note it and I forgot). TA now reading out at 40 ppm, so I may have overshot slightly. I'm aerating now, will check pH after and if it's 7.8 or lower I'm going to add the borax and acid PoolMath calls for to get to 50 ppm borates, and follow with shocking using diclor.
Click to expand...
Be careful using the diclor, you are using it to get your CYA to 30. I have overshot the cya every time but not a biggie, just manage your FC based on where you end up with CYA (per the fc / CYA chart) Once you get your CYA set you will use liquid chlorine to manage your FC.
 
Alwayswantedapool said:
Be careful using the diclor, you are using it to get your CYA to 30. I have overshot the cya every time but not a biggie, just manage your FC based on where you end up with CYA (per the fc / CYA chart) Once you get your CYA set you will use liquid chlorine to manage your FC.
Click to expand...
Yup, will do.

FC down to 6.5 ppm, cc reading at 1.0. Used the 10 mL sample so that was two drops on the cc. An hour or so after I added the initial dichlor I was at 10.2 fc, 0.4 cc (25 mL sample). Haven't used the tub yet. Perhaps I should have washed it out before filling it...

pH was at 8.0 (again), though I didn't double check that after I added the borax and MA, just added both last night, mixed it with the bubbles, and went to bed. 5 drops of acid demand to take it to 7.4, so based on what I looked up in the Taylor tables the first day I added another 1.8 oz MA. Interestingly, (before the MA) the TA was 60 (or 70, I need to be more careful counting drops), not the 40 it was last night. I guess the borax probably has impurities in it.

Anyway, hopefully the pH gets down to below 7.8 and stays there. Tomorrow evening will be the first use, if all goes well. Finally at 101 °F, it's climbing really slow these last few degrees. The garage is probably 55 °F and the concrete is pretty cold, so that can't help.
 
Have to say, that acid demand test is pretty handy. The 1.8 oz I added was based off a rough volume to weight conversion I did off the tables in the Taylor test booklet which I did the first day. The 1.8 oz (weight) MA I added earlier brought the pH down to 7.3. I was aiming for 7.4. I took the tables and did a more exact conversion from fl oz to oz wt, and got that I should have added 1.6 oz MA to bring the pH down to 7.4. Since I added 1.8 oz and got the pH down to 7.3, that seems like the acid test and my conversion to weight tables will be pretty spot on for future use.

I think I'm fairly balanced now. I'll just check it when I check the chlorine every day, add some acid if needed, or check if we use the bubbles. That's unlikely though, as when I was doing the acid/aeration 30 minutes of bubbles could drop the temp 2-3 °F, and that was in the high 80's. Tub can't run the heater with the bubbles on and the cold ambient air just cools the tub really fast, so we likely won't be able to really use the bubbles until summer.
 
Arobbert said:
Note that Dichlor will lower your ph a little so you want to factor that into your calculations.
Click to expand...
Yup. Realized that a tad late when I did a pH test last night. It was down to 7.0. Previously, it was at 7.3, TA was at 40. I happened to have washing soda handy (I made some a couple months back to de-rust an old cast iron pan) so I threw in 10 grams, which was supposed to raise my TA by 8.3 ppm. I didn't want to overshoot 50 since I undershot it twice. Went with washing soda over baking soda as I wanted more of a pH rise to get back to the 7.4-7.6 range.

Tonight it was at 7.3. TA now reading 50 (4th drop made it clear, this morning 4th drop was still green). I'll aerated some more tomorrow morning and see it it'll get up to 7.4-7.6 without adding anything else.

I should be at 25.8 ppm CYA so almost time to switch to bleach.
 
That happened to me recently as well. Borax works better than washing soda for lowering ph while leaving the ak less affected.
There's a product call Easy PH (magnesium oxide) Which has almost no affect on ak. I used this because my ak was already at 55.
Just make sure you achieve all you can by aerating first.
 
Arobbert said:
Borax works better than washing soda for lowering ph while leaving the ak less affected
Click to expand...
BotH INCREASE the pH. Acid Lowers the pH




There's a product call Easy PH (magnesium oxide) Which has almost no affect on ak. I used this because my ak was already at 55.
Click to expand...

i need to investigate what adding magnesium to your water does.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Arobbert said:
That happened to me recently as well. Borax works better than washing soda for lowering ph while leaving the ak less affected.
There's a product call Easy PH (magnesium oxide) Which has almost no affect on ak. I used this because my ak was already at 55.
Just make sure you achieve all you can by aerating first.
Click to expand...
As mknauss pointed out, borax raises pH, which is what I wanted to do. I'm already at the recommended 50 ppm of borates, and I did want to raise my TA a bit because I overshot with acid and it was at 40 ppm. Since my pH was low too, I used washing soda to raise both the pH and the TA closer to the levels I want.

TA is now at 50, and I'd like to get the pH up a bit more. I'll bet I can with some more aeration, but since it's about 50 °F in my garage and the tub has a measly 1300 W heater, it can't currently even hold temp uncovered with no aeration. Couple that with the fact that bubbles without jets is pretty pointless and we don't run aeration except for mixing and for aeration for pH.
 
I meant to say borax and washing soda increases ph. Doh...
Borax raises ph more than ak compared to washing soda. You can do a comparison on the poolcalc.

Here's some info I found on Magnesium Hydroxide which is what Easy PH is (not Magnesium Oxide, my bad). I found that it produces almost no increase in ak and produces a strong increase in ph. I use it if I only want a ph increase.
http://www.phadjustment.com/TArticles/Magnesium_Hydroxide.html

Sorry for the confusion.
 
Arobbert said:
I meant to say borax and washing soda increases ph. Doh...
Borax raises ph more than ak compared to washing soda. You can do a comparison on the poolcalc.

Here's some info I found on Magnesium Hydroxide which is what Easy PH is (not Magnesium Oxide, my bad). I found that it produces almost no increase in ak and produces a strong increase in ph. I use it if I only want a ph increase.
http://www.phadjustment.com/TArticles/Magnesium_Hydroxide.html

Sorry for the confusion.
Click to expand...
That link says magnesium hydroxide isn't soluble above a pH of 7.0 and therefore can't raise the pH above 7.0. Since I was already at 7.0 and wanted to get it up to at least 7.4 that looks like it wouldn't have worked. Sodium hydroxide (lye) would probably work fine though.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply