Bromine Spa Left Unattended

[heykerrdog]

Leaving' on a road trip today. Used advice on this forum for treating a spa before leaving it unattended for an extended time. Here's what I'm doing.

Initial readings:

100 degrees
pH 7.8
Br- 4.5
TA 60

Steps taken before leaving on trip:

Switched spa to SLEEP mode, which heats water to within 20 degrees F. of set temp only during morning and evening 2-hr filter cycles.
Lowered set temp to 80 degrees F.
Added 1 cup 8.25% bleach to raise Br- up to 30+ ppm
Dialed the Life Spa floater all the way out to the very first thread (way beyond all the settings numbers) and filled it with brom tabs (Leisure Time)
Turned off all air jets.
Turned off waterfall.
Spa is covered.

I'll let you know what I have when I return next week.

View attachment 39439

What you see is half of the brom tabs. The other half is inside the blue.

 

[chem geek]

Sounds good. The lower temperature will help and you should have plenty of bromine tabs to last the week -- same with turning off aeration sources to help maintain pH and prevent outgassing of carbon dioxide or of bromine. Ideally you know how much to open the feeder to maintain a bromine level. If it's open too much, you may find a high bromine level when you return, but you can easily deal with that.

 

[heykerrdog]

Returned home this morning, 7/15/2015. Took readings at 02:20am, since I was jacked-up on Mountain Dew.

02:20 am:

The spa has been sitting covered for about 7 days and 18 hours.

Temperature = 90 degrees F. (although it was set for 80, it was also in SLEEP mode, which says it will heat to within 20 of the set temp. I guess it's been warm here, maybe...)

Bromine = 45

pH = 8.0+

TA = 30 and the sample turned yellow.

Nearly all of the brom tablets were consumed.

I removed the spa cover.

I removed the brom tab floater.

At 09:10 new readings taken by my wife.

09:10 am:

Spa uncovered 7 hours. I have not turned the heat back on to normal operation yet.

Brom floater removed.

Temperature = 90 degrees F. (sitting in sunlight now)

Bromine = 47.5

pH = 7.7 (4 drops R-0005 to lower sample to 7.3)

TA = 40 and it turned yellow, not red.

11:20 am:

Added 2.1 oz baking soda to raise TA to 50

Turned on pumps and aerators.

Spa cover off.

Brom floater removed.

13:15 (1:15pm)

Turned spa back to normal operation.

Set temperature to 99 degrees F.

Brom floater removed.

Added approximately 25 gallons of tap water.

19:15 (7:15pm)

95 degrees F.

Br- = 0.5 - 1.0 (some bird droppings in spa as it sat open, probably helped use up some of the Br-)

pH = 7.6, add 2 drops R-0005 to bring sample down to 7.4.

TA = 60

CH = 175

View attachment 39980
Leisure Time Brom Tabs.

View attachment 39981
Comparison of what remained (left pile) after 7 days and 18 hours to the 12 full sized tabs (right stack) that I started with when I left for vacation.

View attachment 39982
The floater after returning home from vacation. It was filled way beyond normal capacity by just catching the last thread of the floater and locking it full open with 12 tabs stacked inside.

 

[chem geek]

How did the bromine go from 45 or 47.5 in the morning to 0.5 - 1.0 in the evening? That's a huge drop in a fairly short period of time.

The TA test will go from blue to yellow instead of from green to red

 

[heykerrdog]

How did the bromine go from 45 or 47.5 in the morning to 0.5 - 1.0 in the evening? That's a huge drop in a fairly short period of time.

The TA test will go from blue to yellow instead of from green to red

I was really surprised at the change. So surprised, we tested the bromine 3 times in the evening after seeing the huge drop. By contrast, that morning, it was literally blood red when I added the R-0870 DPD powder. In the evening, it hardly even got a pink hue. I wondered if my one-time use of the MPS on July 3rd, where I added the 42 teaspoons of MPS and caused the bromine to go so high that I ended up peeing in it to use up the bromine, had somehow changed the chemistry altogether. I know that the garden hose I used to fill the tub was full of water that had been sitting in the hose for the same amount of time that we were away-it was connected at the faucet and had a closed spray nozzle on the end. I wondered if the water in the hose had something in it that the bromine attacked, since that water went into the tub as part of the 25 gallons of water that I added. I also wasn't sure what the overall affect of diluting the water with an additional 25 gallons would be. The tub was uncovered, in direct sunlight all day, and I ran the aerators and jets and pumps for about 4 cycles of 15 minutes each.

Shoot. I don't think I even caught the fact it was supposed to be green instead of blue. I just remember it going to yellow and figuring it was my high bromine level messing up the TA test.

 

[chem geek]

High sanitizer concentrations will bleach out DPD dye but with a FAS-DPD test one usually sees a "flash of pink" when adding powder so just adds more powder to get a color. I suspect it was still high and you missed the flash of pink.

The TA test is still valid even though it has different colors for the transition.