Need to change water?

[JPMorgan]

Our indoor pool runs year round and the water has not been changed in over 2 years. The pool gets minimal use and the water is clean and clear. I'm not having any problems with the water chemistry. The Aquasol Controller keeps the bromine level at a steady 6-7 ppm and pH at a steady 7.5 with the acid feeder. Should I be thinking about a drain and refill or is that not necessary until/ unless I start experiencing some problems? What kind of problems might I start to experience that would indicate it's time for a fresh fill? Thanks for any input on this.

 

[HermanTX]

My water has not been changed in 5 yrs. Although it is an outdoor pool and does have evaporation
You could post a full set of results so that can be reviewed.

 

[Newdude]

What kind of problems might I start to experience that would indicate it's time for a fresh fill

A black swamp. A green swamp is reasonable to fight. Lol.

 

[JPMorgan]

My water has not been changed in 5 yrs. Although it is an outdoor pool and does have evaporation
You could post a full set of results so that can be reviewed.

Br = 7
pH = 7.5
TA = 70
CH = 600
CSI = .19

 

[JamesW]

How many pounds of bromine tablets have been added since the pool was filled?

Can you post all test results?

Can you test the salinity with a K-1766 salt test kit and a calibrated salinity meter set to salt (Not TDS)?

Can you find a local lab that can test for DMH?

A local University Chemistry Lab will usually help if you ask the right person.

Can you test for CBs?

CCs and CBs (Chloramines and combined bromine compounds) are tested the same way.

 

[JPMorgan]

How many pounds of bromine tablets have been added since the pool was filled?

Can you post all test results?

Can you test the salinity with a K-1766 salt test kit and a calibrated salinity meter set to salt (Not TDS)?

Can you find a local lab that can test for DMH?

A local University Chemistry Lab will usually help if you ask the right person.

Can you test for CBs?

CCs and CBs (Chloramines and combined bromine compounds) are tested the same way.

Guessing at least 150 lbs of bromine have been put in the pool.
Today's test results...
Br =11 (added some liquid chlorine yesterday to raise it to the regulated limit)
pH = 7.5
TA = 70
CH = 650
CSI = .22
I don't currently have a salt test kit or salinity meter
Will have to search online for lab to test for DMH
To test for CBs, am I adding 5 drops of R0003 after testing for bromine level and then counting drops of R0871 to clear sample (if I get any pink after adding the R0003)?

 

[JPMorgan]

Just realized there is a different reagent for testing for bromine (R-0872). Is this different than R-0871 (which I have been using)? Will I get different results using the R-0872 reagent?

 

[JamesW]

To test for CBs, am I adding 5 drops of R0003 after testing for bromine level and then counting drops of R0871 to clear sample (if I get any pink after adding the R0003)?

Correct, but use R-0872.

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The Apera Instruments PC60 Multi-parameter Tester/Meter simply tests pH/EC/TDS/Salinity/Temperature for regular aqueous solutions such as hydroponics, aquaculture, pools& spas, tap/drinking water, water treatment, cooling towers, etc.

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Guessing at least 150 lbs of bromine have been put in the pool.

That probably puts the DMH near 500 ppm if the pool is 20,000 gallons.

 

[JamesW]

http://apps.who.int/iris/bitstream/handle/10665/43336/9241546808_eng.pdf

http://apps.who.int/iris/bitstream/10665/43336/1/9241546808_eng.pdf

Facilities using bromine as a sanitiser shall keep the DMH levels no greater than 200 milligrams per litre.

https://ww2.health.wa.gov.au/~/media/Files/Corporate/general-documents/water/PDF/SECTION5_WATER_QUALITY_TESTING.pdf

 

[JamesW]

100 lbs of bromine tabs will add about 125 ppm of dmh to 50,000 gallons of water.

The amount of CYA added by trichlor is roughly the same amount of DMH added by bromine tabs.

I would limit the amount to 60 lbs.

I don't know if your area has a specific limit on DMH, so it might be more of a choice rather than a code

 

[JPMorgan]

Correct, but use R-0872.

Yikes.... for the past 2 years I have been using R-0871 to test bromine levels. Have my results been way off? What's the difference between R-0871 and R-0872?
Thanks for the additional information.

 

[JPMorgan]

We keep the temp around 84-85(F)... so about 29(C). Since the minimum bromine level at that water temp is 4 ppm, I assume 5-6 ppm is a good level to shoot for. Does that sound right?

I would limit the amount to 60 lbs

We go through about 60 lbs of bromine per year. Sounds like we should be changing the water about once per year to keep DMH under recommended limits. If we adopted that practice (fresh fill annually) would we really need those additional test kits? Seems to me that if we did a fresh fill annually that would keep DMH under 200, so no need to do all those tests. (Not sure the HOA would agree to anything more frequent than one fresh fill per year.)

 

[JamesW]

If you use the chlorine test, just multiply by 2.25 to get the bromine result.

 

[JPMorgan]

So, for example, using the 10 ml water sample and R-0871 reagent, if I count 6 drops to clear the sample that would be 3 ppm FC and 6.75 ppm BR... or 1.125 ppm BR per drop. If that's correct, then it sounds like shooting for 5-6 drops to clear (in 10 ml sample) should give me the right level for a water temp maintained at 85(F). Sound about right?

 

[JPMorgan]

Also.... does the accumulation of DMH noted above, i.e. 100 lbs of bromine adds 125 ppm in 50k gallons of water, account for the addition of fill water over the period of time? I'm wondering if we could actually get closer to 75 lbs. of bromine (1 1/2 - 50 lb tubs) before we get to that 200 ppm threshold when fill water is accounted for. That would be an easier way to determine when to drain and refill the pool, i.e., after one 50 lbs tub and one 25 lb of bromine have been added to the pool.

 

[JamesW]

You can carefully track the amount of bromine added to estimate the amount of DMH in the water.

You can monitor the amount of fill water added that is due to water loss other than evaporation to estimate the amount of dilution.

The problem with DMH is that there is no test for DMH that is sold for pool use that I know of.