Painting vs Re-Plastering

[JamesW]

Would this be a good test for UV exposure?

1. Wait for a sunny day and test the bromine in the pool before sunrise.
2. Close the pool to swimmers on that day.
3. Turn off the bromine feeder
4. Test the bromine level again after sundown.
5. If bromine loss is negligible, then I could assume very little UV exposure.

Make sense?

That's a good idea.

Compare losses between day and night to see if there are any significant differences.

Note that turning off a chlorine or bromine feeder just traps the tabs in the feeder and they continue to dissolve and the mixture can get really concentrated, which is not a good idea.

The mixture gets very acidic, corrosive and dangerous.

When you open the feeder valve again, you get a highly concentrated solution of chlorine or bromine being introduced into the system.

It is also dangerous if someone opens the feeder because they can get gassed by the toxic mix.

 

[JPMorgan]

Over the weekend I raised the bromine in our indoor pool to 20 ppm. In 24 hours it fell to 11 ppm. (No swimmers were allowed in the pool during this time.) Would this indicate a SLAM is needed? When I tested for CC (...or CB) today the sample turned pink, but cleared with one drop of R-0003. How do I interpret that in a bromine pool? Could this be part of the problem we are having with some algae in the pool at this time? Maybe it just needs a good SLAM to clear things up until we drain and fill again??? I assume the SLAM procedure is the same for a bromine pool as it is for a chlorine pool except that I am raising bromine to 20 ppm. Is a 2 ppm drop overnight acceptable to pass the SLAM in a bromine pool?

 

[JamesW]

In 24 hours it fell to 11 ppm.

Can you differentiate between day and night?

today the sample turned pink, but cleared with one drop of R-0003.

R-0871?

Could this be part of the problem we are having with some algae in the pool at this time?

The problem is probably DMH.

Is a 2 ppm drop overnight acceptable to pass the SLAM in a bromine pool?

2 is probably passing, but as close as possible to 0 is ideal.

 

[JPMorgan]

Can you differentiate between day and night?

R-0871?

I can track day and night bromine loss the next time I do it. I did not this time. Would it be best to raise to 20 ppm at night and then check the next morning for any loss?

Yes.... after adding 5 drops of R-0003 to the sample it took 1 drop of R-0871 to clear.

 

[JPMorgan]

Note that turning off a chlorine or bromine feeder just traps the tabs in the feeder and they continue to dissolve and the mixture can get really concentrated, which is not a good idea.

The mixture gets very acidic, corrosive and dangerous.

When you open the feeder valve again, you get a highly concentrated solution of chlorine or bromine being introduced into the system.

It is also dangerous if someone opens the feeder because they can get gassed by the toxic mix.

I'm letting the bromine feeder empty and can just dose the pool with liquid chlorine for now while I conduct the test for bromine loss during a sunny day (in order to assess loss due to UV exposure). This should avoid any problems noted above.

 

[JPMorgan]

After reading some past posts on sanitizing indoor pools with chlorine it seems to me some UV exposure would be a good thing.... then run the pool with about 20 ppm CYA (if allowed) and maintain 3-4 ppm FC in the pool.

 

[Mdragger88]

The suggestion for 30ppm cya even in an indoor environment is multiple fold-
*Its hard to measure cya lower than 30
* it allows for higher target/residual fc levels so minimum isn’t as easily broached without also being too harsh on people and equipment which is important in a semi public setting that could suddenly have an increased bather load without the caretaker present.

As mentioned you can always go back to bromine from chlorine without exchanging water & you are already are managing a chlorine pool so it should simplify things a bit going the chlorine route. At least for now.
You may experience chloramines being an indoor pool but there are ways to help mitigate that problem as James listed previously.

 

[JPMorgan]

I would like to know how to interpret these test results:

• Using a 25 ml water sample for the FAS-DPD test, it took 28 drops of R-0871 to clear the sample... so that gives me 14 ppm of bromine, correct?
• Then I added 5 drops of R-0003 to the sample and the sample turned slightly pink. Is that combined bromine?
• If it takes 6 drops of R-0871 to clear the sample (after adding the R-003), how do I interpret that? Is that ppm of combined bromine? If so, how much?
• Should I SLAM the pool until I get no pink after adding the R-0003, i.e., no combined bromine?

I started SLAM at 11:00 am today. Raised bromine level to 20 ppm. At 3:00 pm it was at 14 ppm and I raised it to 20 ppm again. It is a sunny day with lots of sun coming through the windows along one side of the indoor pool. I will test again at 7:00 pm and and raise the level back to 20 ppm, if necessary. Then, I will check the level again before sunrise to see what the overnight bromine loss is. Should I continue this process until I have less than 2 ppm loss of bromine overnight in order to clear the pool of any contaminants? The pool water is very clear.

 

[JamesW]

Using a 25 ml water sample for the FAS-DPD test, it took 28 drops of R-0871 to clear the sample... so that gives me 14 ppm of bromine, correct?

28 drops is 5.6 ppm chlorine or 12.6 ppm bromine.

Then I added 5 drops of R-0003 to the sample and the sample turned slightly pink. Is that combined bromine?

It is an oxidizer that does not react with the R-0870 powder.

R-0003 is iodide and the oxidizer oxidizes the iodide to iodine, which reacts with the R-0870.

There are many different oxidizers that can cause a reading for the second part of the test.

MPS will react as will chloramines, brominated compounds, bromate, etc.

Theoretically, Combined Bromine should react in the first part of the test and not in the second part.

In practice, the "CC" part of the test for a bromine pool or spa will show results more often than most chlorine pools or spas.

Pools and spas can accumulate disinfection byproducts (DBPs).

https://www.aquaticsintl.com/facilities/maintenance/the-abcs-of-dbps_o

If it takes 6 drops of R-0871 to clear the sample (after adding the R-003), how do I interpret that? Is that ppm of combined bromine? If so, how much?

6 drops is 2.7 ppm of bromine "equivalent" oxidizer.


Chlorine and Bromine can react with organic compounds to form disinfection byproducts like Trihalomethanes (THMs) and haloacetic acids (HAAs).

 

[JPMorgan]

6 drops is 2.7 ppm of bromine "equivalent" oxidizer.

I understand how you got the number (6 x .2 x 2.25 = 2.7). No need to worry about this then?

 

[JamesW]

I understand how you got the number (6 x .2 x 2.25 = 2.7). No need to worry about this then?

It indicates that there is something in the water that should not be there.

I would dilute to remove the contamination and to reduce DMH levels.

Maybe consider adding UV.

 

[JPMorgan]

Here are the bromine readings I recorded during SLAM that I started yesterday at 11:00 am:
11:00 am - raised bromine to 20 ppm
3:00 pm - 14 ppm (raised to 20 ppm)
7:00 pm - 18 ppm (raised to 20 ppm)
8:00 am - 18 ppm
So.... at last check I lost 2 ppm bromine over 13 hours (7:00 pm to 8:00 am). Water is crystal clear and balanced. We need to open the pool today, so I did not raise the bromine back to 20 ppm this morning. I forgot to add the R-003 drops to the water sample this morning, so I will test water again before we open to see where things stand on the 2nd part of the test.

How much dilution would you suggest... and at what level is that reading on the 2nd part of the test insignificant, i.e. if the sample clears with one or two drops of the R-081 would that be acceptable?

 

[JamesW]

How much dilution would you suggest

Probably about half of the water needs to be replaced over the next few weeks.

No need to try to do it all at one time.

Figure out how to slowly add and remove water at the same time.

If you added and lost 0.23 gallons per minute, the water level would stay constant and you would use about 10,000 gallons of water in 30 days.

It is the least efficient method, but it reduces the disruption to operations.

You would need to make sure that the process was done while being monitored to avoid problems.

Maybe an exchange rate of 1 gpm during the day so that you can monitor.

and at what level is that reading on the 2nd part of the test insignificant

Keep it below 1.0 ppm bromine.

 

[JamesW]

Can you get a K-1766 salt test kit and a digital salinity meter and post the salinity readings from both?

These will help assess the TDS and they can help assess the effectiveness of the dilution.

 

[JPMorgan]

Can you get a K-1766 salt test kit and a digital salinity meter and post the salinity readings from both?

These will help assess the TDS and they can help assess the effectiveness of the dilution.

Are these what I need?

https://www.amazon.com/gp/product/B0BML9TG53/ref=ox_sc_act_title_2?smid=A2LO4ZH6YDQFNN&psc=1

https://www.amazon.com/gp/product/B001DO35EU/ref=ox_sc_act_title_3?smid=AUEJ0SMSO197F&th=1

 

[JamesW]

Those should work.

Get some calibration solution for the meter to verify accuracy.

 

[JPMorgan]

Keep it below 1.0 ppm bromine.

On last test 2 drops of R-0871 cleared the sample, so... 2 drops x .45 per drop = .9 ppm. Looks like we're okay for now. I will shock weekly for a while to see if I can get that down to 0.

 

[JPMorgan]

Figure out how to slowly add and remove water at the same time.

I understand the concept here, but by doing it this way aren't you removing some of the good water with the bad water eventually. Wouldn't it be more efficient to dump all the bad water, then re-fill with good water?

 

[JamesW]

I think that the DMH is causing problems like a chlorine pool with a 200 ppm CYA.

The water becomes unmanageable.

The salinity tests can help assess what is in the water and it will help estimate the DMH levels.

The K-1766 measures chloride and bromide.

The digital meter measures all ions in solution, so this can help assess how much of the TDS is "Salt" and how much is something other than salt.

 

[JamesW]

I understand the concept here, but by doing it this way aren't you removing some of the good water with the bad water eventually. Wouldn't it be more efficient to dump all the bad water, then re-fill with good water?

Yes, doing it all at once is more efficient.

You can do it whichever way you feel works better for you.

Draining can involve risk of floating the pool so be sure that the amount drained is not unsafe.

Draining - Further Reading

www.troublefreepool.com