Confused about sanitizer

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dsime42

0
Sep 29, 2013
15
~Stockton, Ca
OK
So I refilled, and ahh som'd my "spa" and now I'm trying to get the chemistry correct again.

I had shock level of bleach in it and found that the PH test (R-0014) turned magenta
I uncovered the spa for about four hours in full sun and sanitizer levels went to ~0

I used PoolMath to get my water to
PH 7.5
TA 80
CH 130

And my test strips were saying that FC was between 0 and 2 depending on how cross-eyed I looked at it.
I don't have a test for FC as I normally run bromine

Things were looking up
I decided to go to the next step and added the bromine and ~ 2oz of bleach to activate it (from low FC level)
Looking good but the sanitizer level went high around 15ppm (5 drops X3 for 25ml sample) on my DPD test (R-870/R-872)
added floater with three 1" bromine tabs

Ignoring the non-perfect reading on the Bromine.
TA and CH stayed pretty much the same as did the PH

On to the Final Initialization ... ...
Added 24 oz (by weight) of 20 Mule Team and 26 oz (by volume) of 14.5% MA

PH went magenta
Bromine went to 39????? (13 drops X3 for 25ml sample)

What???? :shock:
OK, been here done this :cool:
Uncovered spa and let the sun bathe it in UV

Bromine went to NIL (<2 drops X3 for 25ml sample)
PH still magenta :confused:
Next Steps?
 
With the FAS-DPD test using R-0870 and R-0872 (bromine) and a 25 ml sample, 1 drop of titrate = 0.5 ppm of bromine. So, if it takes 5 drops of titrate to turn the sample clear, your bromine level would be 2.5 ppm, not 15 ppm. I'm not sure where your confusion comes in multiplying the number of drops by 3, but it should be multiplied by 0.5.

I purchased a graduated cylinder from TFTestKits . com and use a sample size of 12.5 ml so that I get 1.0 ppm of bromine for each drop. The graduated cylinder I purchased is better than the Taylor one, because it has black lines that you can actually see, and one line for each ml. You can use a sample size of 10 ml and multiply by 1.25 to get ppm, and this would be more economical with the titrant.

According to PoolMath in 400 gallons, your adding of borax and muriatic acid should have resulted in pH and TA being approximately the same as when it started, while adding 51 ppm of borates. So I don't know what would cause your pH reading to be off scale.

For safety, you should try to keep bromine between 4 - 6 ppm and never let it fall below 3. I actually try to keep my tub between 6 - 10 ppm as I find the water stays clear at those levels, whereas I had some problems when I was targeting lower levels.
 
Thanks for your advice, but my problem was operator error.
I put in the 26 oz of MA as two 12 oz cups and 2 oz
However, since a cup is only 8oz, ... ... ...

PH reading was probably too high for the reagent hence the "error" reading :-(

- - - Updated - - -

Yes, I actually ahh-some'd three times.
Once with the diverter "this" way, once with the diverter "that" way and finally once with the diverter centered (giving somewhat reduced flow)
Drained and filled, jets run for "a while"
Drained and filled.
Starting point
 
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