What can cause sanitizer to read high?

[bulmer4nc]

Every once in a while (like now) we show readings of very high bromine when testing the water (somewhere between 6 and 10ppm).  Nothing seems to be different and there's not much bromine in the dispenser.  I've only put in 2 tablets in the past week.  Is there something that can cause the readings to be wrong?  Or is there something that could be causing the bromine level to actually be that high?  On the test strips that I use it showed both 'free' and 'total' bromine to be high.  I'm not quite sure what the difference is between the two.

Any ideas?

[Chas]

When the Bromine level gets too high, you need to take the floating feeder out - or take the tabs out of the feeder if you have some type of built-in device - and add people.

That's one drawback to Bromine: once it gets going, it tends to climb rapidly and stay up for a while.

[rocket]

Chas is right.  The bromine feeder is convenient but does have some negatives like what you are experiencing.  If you like bromine, I would recommend granular.  

[Dr. Spa™ Ret.]

Copied from http://www.rhtubs.com/BROMINE.htm


When bromine is added to a spa it's in the form of bromide ions. It then activated with an oxidizer to form hypobromous acid. Hypobromous acid is the killing form of bromine. When hypobromous acid reacts with an organic contaminant it's reduced back to bromide ions. The bromide ions can then be reactivated back into hypobromous acid by the addition of an oxidizer. This is somewhat of a continuos cycle with bromine sanitized spas.

If 100 percent of the bromide ions became hypobromous acid and 100 percent of the hypobromous acid returned to bromide ions, you would never again have to add more bromide salt. But hypobromous acid can react with certain chemicals in the water that tie up the bromide ions and prevents them from becoming free bromide ions in the water. This happens when hypobromous acid produces bromate or bromoform for instance. There are many other combinations that tie up the bromine so it can not become a free bromide ions. For this reason more bromine salt or bromide ions need to periodically be added. The level of bromide ions should not go below 15 ppm.

The basis behind 2-part liquid bromine sanitizing systems is to add a salt of bromine (sodium bromide) to the water to get bromide ions and then oxidize the bromide ions with an oxidizer such as monopersulfate (MPS), hydrogen peroxide, percarbonate, ozone or any compound of chlorine to produce hypobromous acid. You need a minimum of 15 ppm of bromide ions for an oxidizer to work and to provide a “bank” of bromide ions for an oxidizer to react with.

Bromine tablets are typically 1-bromo-3-chloro-5,5-dimethylhydantoin. When added to water they hydrolyze to become hypobromous acid. With bromine tablets a separate oxidizer is not necessary to make hypobromous acid, it is already an ingredient in the tablets. When the hypobromous acid reacts with a contaminant and is reduced, it becomes a bromide ion. You then get a build up of bromide ions in the water. After a while, you could just start adding an oxidizer to reactivate the bromide ions to hypobromous acid, but most people don’t, they just add more bromine tabs.

Currently is no way to test water to find out how much bromide ions are in it. This is because the same test that measures bromide ions also measures chloride ions and all water has chloride ions in it. Other than making an educated guess, there's no way to tell when the bromide ion level is too low. The 2-part bromine manufacturers know this and recommend that you add some bromide ions (liquid bromide salts) every few weeks or so.

Realistically, a bromine sanitized spa can not be switched over to chlorine, if there's still bromine in the water. All the chlorine added to the water is going to convert bromide ions into hypobromous acid. As long as there's 15 ppm or more of bromide ions in the water, all the chlorine added is going towards converting bromide ions into hypobromous acid, none of it will provide a chlorine residual. The spa will continue to be bromine sanitized until the bromide level gets below 15 ppm. But there is no test kit for measuring just bromide ions in the water and therefore no way to know when the bromide level is below 15 ppm. It could take a week. It could take 2 months.

[spahappy]

The most common factor is a slow down in useage. If the activity level in the spa has remained the same and the bromine still spikes it may be due to shocking the water.  I belive thats what I think I just read in the previous post by Dr. Spa.

Spahappy

[bulmer4nc]

The most common factor is a slow down in useage. If the activity level in the spa has remained the same and the bromine still spikes it may be due to shocking the water.  I belive thats what I think I just read in the previous post by Dr. Spa.

Spahappy

So you're saying that if I shock too much it may spike the bromine?   My dealer had told me that you can't over shock a spa.  Last weekend I was dealing with cloudy water that was only 2 weeks old and I shocked twice in 3 days.  The bromine level has been elevated since then.  I also shocked yesterday as it has been a week and that is my normal interval.  The tub was still getting used pretty much every day (not quite as much by the kids) so there really hasn't been a slowdown in usage.

For now I've taken what was left out of the bromine basket (only two fragments were left).  Should I just wait it out until it goes back down?  (and add poeple as Chas suggested)

I guess the next question is... Is it alright to use the spa when the bromine level is elevated?

[bulmer4nc]

Another question - when the bromine level is elevated does it affect anything else with the water?  Do you treat alk / ph the same way or would you expect to see them show up as elevated or low?

[HotTubMan]

Depends on the bromine source. SpaGuard Bromine Tablets- pH 4 SpaGuard Brominating Concentrate (1 part bromine powder)- pH 7.

Sounds like you are using tablets. This most likely is erroding your TA and can eventually affect pH.

HTM

[bulmer4nc]

We're using the Leisure Time Bromine Tablets and what I've noticed is that the Alk appears to be low and the ph seems to be high.  I've added Alk Increaser a couple of times.  It seems to get upt 100 and then drop again.  Should I just wait until the bromine level drops until I worry about trying to get alk/ph correct again?

[bulmer4nc]

BTW - This is the ingredient list:

ACTIVEINGREDIENTS:
1-bromo-3-chloro-5, 5-dimethythydantoin ……………. 60.0%
1,3-dichloro-5, 5-dimethylhydantoin ………………….. 27.4%
1,3-dichloro-5ethyl-5methythydatoin …………………. 10.6%

INERTS ………………………………………………… 2.0%

Available bromine ……………………………………… 39.2%

Available chlorine ……………………………………… 44.4%



Not really sure what those number mean, but maybe it helps in telling me if the bromine is affecting alk / ph.

[poolboy34]

HTM is right on the money, Bromine Tablets have a lower pH and will "errode" yout TA over time.  Try keeping the TA a tad higher say between 125-150, this should alleviate the problem.  Also you might want to remove the floater when you are using the spa.

Jason,
Store Manager for a D-1 & Caldera Dealer

[Chas]

Also you might want to remove the floater when you are using the spa.
Jason,
Store Manager for a D-1 & Caldera Dealer

This is a very important tip if your bromine continues to climb. The typical floating feeder will feed at a much greater rate in turbulant water, ie: jets running or people moving about.

[bulmer4nc]

This is a very important tip if your bromine continues to climb. The typical floating feeder will feed at a much greater rate in turbulant water, ie: jets running or people moving about.

In our case we don't use a floater, we use the built in basket in the filter door.  Do you recommend trying to get them out of there in this case too?

[bulmer4nc]

Seems to be getting back to normal.  

So how do I prevent this from happening in the future?  

It sounds like in our case it's probably better to keep the Alk up higher (around 120) so that if the bromine does elevate a bit it won't drop the alk so low and raise the ph.

Any other suggestions on what to do preventatively?

[Chas]

Well, that's one downside to built-in feeders, especially if they are in the skimmer door. They put them there on purpose: to feed more when the jets or filtration system is moving water past them, and it works. But if your use of the tub is such that the level gets too high, then I would suggest going to a floating feeder or switching to Dichlor. If you do go to a floating feeder, it would allow you to try "Brilliance" from the makers of Baqua. I tried it and liked it.