Does too much Bromine increase Acid demand?

[IlChengis]

Hello All,
I've recently started maintaining my SPA (approximately 400 gallons) and recently "upgraded" from test strips to this test kit:
http://www.amazon.com/gp/product/B00107039U/

It has been a nice improvement, but I am still getting used to it and the instructions do leave a bit to be desired.

This past weekend, I checked Bromine level and it was quite low, so I added approximately 110 grams (~4oz).
I know, it's too much, but in my defense The test-Kit's instructions don't mention how much bromine or chlorine to add, when needed.

I also checked Acid demand, and based on the chart, it said it needed approximately 1oz (3 drops of "acid demand" solution brought colour to down to expected level)... which I added (muriatic acid).

I checked again a few days later, and the Bromine level is high (as expected due to my error), but the Acid Demand skyrocketed too!
I dropped twentyfive (25!) drops of "acid demand" solution and the color was still unchanged (normally 3-4 drops are all that I ever needed).
I stopped at 25, not wanting to waste the entire bottle.

Could you please advise me on what to do next? I suspect the Bromine level has dropped by now, since it's been almost a week.

Also, one more piece of data: I've used this test kit 4-5 times so far, and everytime it seems like I need to add about 1oz of Acid, so I've been adding about 1oz of muriatic acid to it every week.

Thank you in advance for your help!

 

[linen]

Welcome to tfp, IlChengis

The ph test is not valid when your Free Bromine level is above 22.5 ppm (and depending on your ph reagent maybe even lower). Wait until you have the bromine level measurable in the range of your test kit (10 ppm I believe) then retest ph.

 

[IlChengis]

Welcome to tfp, IlChengis

The ph test is not valid when your Free Bromine level is above 22.5 ppm (and depending on your ph reagent maybe even lower). Wait until you have the bromine level measurable in the range of your test kit (10 ppm I believe) then retest ph.

Thanks, Linen, this makes perfect sense.

I'll test again today and report back.

 

[linen]

What color is the Bromine test showing right now?

The color can give you an approximation of what your current level is...if the sample turns a particularly vivid yellow the Total Bromine level is between 10 and 30, light orange is between 20 and 40, dark orange is between 30 and 60, and brown is 60 or higher.

 

[IlChengis]

What color is the Bromine test showing right now?

The color can give you an approximation of what your current level is...if the sample turns a particularly vivid yellow the Total Bromine level is between 10 and 30, light orange is between 20 and 40, dark orange is between 30 and 60, and brown is 60 or higher.

If I recall correctly, it was dark orange.
I will check again today and report back, although I suspect it will be lighter in colour.

 

[JamesW]

What is your TA?

 

[IlChengis]

Hi Linen,
I checked Bromine level again this past weekend and it looked to be within spec, it had dropped considerably.

JamesW, by TA you mean Total [s:2gk9llzy]Acidity[/s:2gk9llzy] Alkalinity, correct? I am not sure, I'd have to test it with my kit.
I will likely test again tomorrow afternoon and report back on all the results.

Thank you.

 

[linen]

Have you rechecked your ph (with the bromine level below 22.5) yet?

Yes, JamesW means Total Alkalinity.

 

[IlChengis]

Have you rechecked your ph (with the bromine level below 22.5) yet?

Yes, JamesW means Total Alkalinity.

I hope to make it home before it gets dark, so I can do a full set of tests and report back.

Otherwise I'll test Thursday. Results coming soon.

 

[IlChengis]

Gentlemen,
I managed to test again last Thursday.
Here are the results (sorry, I had limited internet access over the weekend):

• Bromine: ~4.4 or a bit higher[/*:m:3r6m63z7]
• pH and Acid Demand: right around 8.2[/*:m:3r6m63z7]
• Acid Demand (same sample ^^^): took two drops of solution #4 to bring down to ~7.4 (<= based on table, 4/5oz of Acid are needed)[/*:m:3r6m63z7]
• Total Alkalinity: 150 (15 drops to a defined yellow/clear colour)[/*:m:3r6m63z7]

Thank you for the help.

 

[linen]

Your TA is high and will continue to push your ph up. I would use the aeration method to get the TA down to ~ 70 ppm. It is easy with a tub since most have aerators built in. Drop your ph down to ~ 7.2 to start, then aerate until the ph is at 7.8 then drop the ph down to 7.2 and repeat this process until the TA is down.

 

[IlChengis]

Your TA is high and will continue to push your ph up. I would use the aeration method to get the TA down to ~ 70 ppm. It is easy with a tub since most have aerators built in. Drop your ph down to ~ 7.2 to start, then aerate until the ph is at 7.8 then drop the ph down to 7.2 and repeat this process until the TA is down.

Thank you Linen.
I wasn't sure of which areation method you referred to, so I did some searching.
Would this be a good post to follow, for my situation?
pool-school/lowering%20total%20alkalinity

Thank you,

-Walter

 

[linen]

Yep, thats the one...lowering TA in a spa is usually easy since the air jets do it fast. Your welcome

 

[IlChengis]

Yep, thats the one...lowering TA in a spa is usually easy since the air jets do it fast. Your welcome

Thanks Linen.

So, I'll start with two quick questions:

The post (and your suggestion above) says to add acid until pH is about 7.2.

What is the Acid Quantity and Rate I should employ to bring it down to 7.2?
How do I know that the pH is dropping because of the Acid, and not because of Bromine evaporation?

 

[linen]

Use the PoolMath calculator: http://www.troublefreepool.com/calc.html

How do I know that the pH is dropping because of the Acid, and not because of Bromine evaporation?

I am not sure I understand this question...but if your free bromine is above 22.5 ppm, it can effect the ph reading, but below 22.5 ppm, what you read for ph is what it is (no matter the Free bromine value).