Balancing after No Drain Acid Wash?

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Apuri said:
Ha! Thanks to help from all of you.

Ok. So finally I got to TA of 70ppm, pH is still low, 2 base test drops to get to 7.0

So I am guessing next round will be about 2 lbs of Borax (7.0 to 7.4 pH per Pool Math)... and then end the day with about 60 oz of 8.25% bleach (0 to 4 TC as per Pool Math).

Does that sound about right?
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You may or may not get the pH rise you want, but it seems like a sound plan to me.
 
Im with Richard. Sounds like a plan. Your getting close, might have to do tweaking, but at least it sounds like you're out of the danger zone.

Apuri said:
Ha! Thanks to help from all of you.

Ok. So finally I got to TA of 70ppm, pH is still low, 2 base test drops to get to 7.0

So I am guessing next round will be about 2 lbs of Borax (7.0 to 7.4 pH per Pool Math)... and then end the day with about 60 oz of 8.25% bleach (0 to 4 TC as per Pool Math).

Does that sound about right?
Click to expand...
 
Because it was so low is the easy answer. You took it way, way down with all the acid, so there was no buffering capacity left in the water at all. It was simply over loaded with acid.

Start adding Borax until you reach 7.4 and stop. Give it some more time, retest the pH and see how it levels. No more Baking Soda. Don't over shoot, or you'll be back to the acid roller coaster.

Once it stabilizes, get a new full set of numbers up.
 
Apuri said:
I tested again this morning. Here are the results
TC: 3.6
pH: 7.0
TA: 70 ppm

Why didn't the pH rise as much? You had predicted that yesterday itself, curious about the mystery behind it :)

Also, what are the next steps I should take?
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What I did was look at the base demand test and worked backwards from that using Effects of Adding Chemicals to see how much pH rise you should get. But pH is a logarithmic function, not a straight-line relationship, so at best you get a close approximation. That's why I suspected the rise wouldn't be as high as you desired. But it's better to work up to a level, rather than try for a one-shot massive adjustment. As it says near the bottom of poolmath:
Note: pH calculations are not exact. These numbers are only suggestive of the relative magnitude of the pH change you can expect. Small changes, +-0.4, with pH between 7.2-7.8, TA around 80-120, and Borate near zero will be approximately correct. The further you go from those ranges the less these pH changes will correspond to reality.
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Now that you're actually on the pH test scale, things should go smooth. You probably won't need to use the base demand test again. Poolmath will do the job easier.

Finish fine-tuning the pH and keep the FC adequate for your CYA level. That's really about it. In a day or two, run the full battery of tests again and post the results. If something needs adjusting, I'm sure people will point it out.
 
makes sense. I will start adding Borax is small quantities till I reach 7.4. Thanks.

Two more questions I have:

- I read somewhere that aeration increases pH. I have a waterfall and fountain installed on the pool for aesthetics, how much do these effect the overall pH?

- My CYA is at 3.0 right now. Do I need to increase it so the Chlorine level stays more stable?

Thanks again for all the guidance I have received here in the last 24 hours. You g
Patrick_B said:
Because it was so low is the easy answer. You took it way, way down with all the acid, so there was no buffering capacity left in the water at all. It was simply over loaded with acid.

Start adding Borax until you reach 7.4 and stop. Give it some more time, retest the pH and see how it levels. No more Baking Soda. Don't over shoot, or you'll be back to the acid roller coaster.

Once it stabilizes, get a new full set of numbers up.
Click to expand...
 
aah! the fun with logarithmic scales! Thanks for solving the mystery for me :)

Richard320 said:
What I did was look at the base demand test and worked backwards from that using Effects of Adding Chemicals to see how much pH rise you should get. But pH is a logarithmic function, not a straight-line relationship, so at best you get a close approximation. That's why I suspected the rise wouldn't be as high as you desired. But it's better to work up to a level, rather than try for a one-shot massive adjustment. As it says near the bottom of poolmath:

Now that you're actually on the pH test scale, things should go smooth. You probably won't need to use the base demand test again. Poolmath will do the job easier.

Finish fine-tuning the pH and keep the FC adequate for your CYA level. That's really about it. In a day or two, run the full battery of tests again and post the results. If something needs adjusting, I'm sure people will point it out.
Click to expand...
 

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If your water is crystal clear, and there is NO sign of visible Algae you may be ok. If so, and you are reasonably certain you killed all the Algae, take the Cya up a little.

If no, or unsure to any of these you should complete a SLAM procedure.
 
Yes, algae is all dead and water was crystal clear before I did the acid wash to clean the calcium buildup. Water still is very clear (except for being a bit soapy/cloudy yesterday when i added baking soda). How much should I raise the CYA to? I have a concrete pool.

Also, can you comment on the other question from morning:
"- I read somewhere that aeration increases pH. I have a waterfall and fountain installed on the pool for aesthetics, how much do these effect the overall pH?"


Patrick_B said:
If your water is crystal clear, and there is NO sign of visible Algae you may be ok. If so, and you are reasonably certain you killed all the Algae, take the Cya up a little.

If no, or unsure to any of these you should complete a SLAM procedure.
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50 is a good target for the CYA. I'd suggest you enjoy things a few days before you start messing with too much too fast. It's easy to raise CYA. It's hard to lower it if you overshoot.

You're just going to have to learn your pool's personality. Experiment with filter run times and adjusting the flow through the waterfall and fountain and see how that affects the pH.
 
I ran a test this morning...
FC: 2
PH: 8
TC: 90
CYA: 30
I had last added Borax 3 days ago and stopped once pH reached 7.4 and TC was around 80. What could have caused the pH to jump so dramatically in 3 days? I had my pool pump running about 6 hours daily with the waterfall.

Richard320 said:
What I did was look at the base demand test and worked backwards from that using Effects of Adding Chemicals to see how much pH rise you should get. But pH is a logarithmic function, not a straight-line relationship, so at best you get a close approximation. That's why I suspected the rise wouldn't be as high as you desired. But it's better to work up to a level, rather than try for a one-shot massive adjustment. As it says near the bottom of poolmath:

Now that you're actually on the pH test scale, things should go smooth. You probably won't need to use the base demand test again. Poolmath will do the job easier.

Finish fine-tuning the pH and keep the FC adequate for your CYA level. That's really about it. In a day or two, run the full battery of tests again and post the results. If something needs adjusting, I'm sure people will point it out.
Click to expand...
 
18 hours with a waterfall going could easily raise the pH to 8. When I was battling high TA, I set my spa into full action so the water looked like it was boiling and got that much pH rise in a few hours. Also, We use TA for Total Alkalinity. TC is Total Chlorine (FC+CC= TC) It gets confusing if you switch abbreviations.

Anyway, now you need to add a bit of acid to lower pH. If there's some way to reduce the flow through the waterfall, do it. You don't want it all the way off otherwise there will be no chlorinated water flowing through the plumbing.
 
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