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How to use Bromine (3 step method)

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(I finally found the post that I made back in 2010 on setting up 3 step bromine for a hot tub so I am reposting it here with a few edits to update the embedded links so they work and improve the clarity of the procedure. Enjoy!)


When testing water do NOT use strips, get a good drop based test kit. Your best bet for Bromine if you are in the US or Canada is the Taylor k-2106 and for chlorine the K-2006 (NOT the K-2005). THE TEST KIT IS PROBABLY THE MOST IMPORTANT THING YOU CAN OWN FOR EASY SPA MAINTENANCE. GET A GOOD ONE! I cannot stress this enough!!!!! If the K-2106 is not readily available in Canada you can use the K-2006 for bromine by testing for Free Chlorine and multiplying the results by 2.25 to get Total Bromine. You do not need to test for combined bromine (combined chlorine test) not cyanuric acid in a bromine system.

On to bromine:

1. fill the spa and balance the water.Do not turn the heat up yet. If you have well water or know your water has metals then add a metal sequestrant at this point. You will need to continue with weekly maintenance doses of the metal sequestrant if your water has metals. A better solution is to fill from a water softener or purchase a "spa stick" filter that attaches to your hose to fill the spa to help remove the metals.

A,adjust TA to 50-70 ppm (here is a detailed explanation and howto on lowering TA if it's too high),, raise TA with baking soda if it's too low,, it's the same chemical sold as TA increaser for much less money!

B. Once TA is in range then adjust pH to between 7.4 and 7.8 Use dry acid (or muriatic acid) to lower pH if too high (8.0 and above). If the pH is too low (7.2 and below) either aerate the water to outgas CO2 and bring up the pH or use borax from the laundry aisle to raise it..Do NOT use pH up because it will make your TA go too high!!!!!!!! pH up is sodium carbonate, also known as washing soda and raises both pH AND TA!

C. IF you calcium hardness is below 130 ppm raise it to 130-150. If it is above 400 then add an anti stain and scale or calcium reducer to the spa weekly. If it is between 130-400 you are fine.

2. If you are not in Canada Add 1/2 oz of sodium bromide per 100 gallons of water to create your bromide reserve in the water. This is the MOST important step with a bromine spa and the one most people ignore. If you omit this step you will not have a bromine spa for several weeks until enough tablets dissolve in the water to create the bromide bank and you will be running chlorine until the bromide bank forms! Sodium Bromide is available in packets and jars from several companies. You will need to re add it on each drain and fill.

Make sure that you get sodium bromide in either powder or liquid form that is sold to start the bromide reserve or 'bromide bank' and not a one step bromine product that is a mixture of mostly dichlor and a little blt of sodium bromide. READ THE LABEL! It should only contain sodium bromide (and water if in liquid form).

Sodium bromide has been outlawed in Canada except as part of 'one step' bromine sanitizer products that are a mixture of sodium bromide and dichlor. A workaround is to use such a product for the first few weeks to build your bromide bank. The ingredients should be sodium bromide and dichlor (sodium dichloro-s-triazinetrione).

3. Shock the spa to 'activate' (oxidize) the sodium bromide into hypobromous acid (this is your 'bromine' sanitizer that you test for with your strips or test kit.) You can use MPS to shock but chlorine works just as well if not better and is much less expensive. One of the best sources of chlorine you can use with a bromine spa is sodium hypochlorite and that can also be found in the laundry aisle. It is ordinary liquid chlorine bleach. You want the regular, unscented bleach, not a thickened or scented one. It will come in either 5.25% or 6%. Read the label to see which you have. Use 3 oz (6 tablespoons) of the 5.25% or 2.5 oz (5 tablespoons) of the 6% per 100 gallons of spa water to shock. Your bromine will go very high. Uncover the spa and circulate until the bromine drops below 10 ppm before you use the spa. Now heat the spa up to temperature. If you are in Canada you want to use your one step product to shock to about 15-18 ppm Total Bromine or you can shock with bleach and just let the bromide bank build up in time,

4. Put in the floater with your bromine tabs (which usually contain BOTH bromine and chlorine to activate the bromine, btw) and adjust the floater to maintain your bromine at about 4-6 ppm. this can take a bit of trial and error. Check your pH and bromine before you go in each time and if bromine is low add a few tablespoons of bleach and retest until it is above 4 but below 10 ppm. It really only takes seconds for the chlorine to oxidize your bromide reserve into bromine sanitizer. If pH is not between 7.2 and 8.0 then you should adjust it before entering the spa and wait about 30 minutes then retest it to make sure it is in the proper range. If both are off then adjust pH first then the bromine. YOU CANNOT ADJUST THE Ph WHEN THE SANITIZER LEVELS ARE HIGH BECAUSE OF AN INTERACTION BETWEEN HIGH SANITIZER LEVELS AND THE PHENOL RED INDICATOR USED TO TEST PH! It does not matter if the test is done by liquid reagents or strips. Most test kits and strips will not give accurate pH measurements if the sanitizer is above 3-5 ppm . Taylor kits are good up to 10 ppm. If it's higher than that you need to wait for sanitizer to drop before testing and adjusting pH. The only work around is a properly calibrated pH meter.  If your bromine is always low open the floater a bit more. If high then close it down a bit. If it is above 10 then take out the floater and open the spa until the bromine level drops below 10 before entering the water and close the floater down a bit. Once you get the floater adjusted the bromine level will stay pretty constant and it becomes much easier! Remember to keep tablets in the floater at all times!

You are done!

Weekly test pH, Keep pH between 7.2 -8.0 and then when you have finished adjusting shock the spa with bleach just like when you added the sodium bromide but you do not need more sodium bromide. Add anti scale or calcium reducer if your calcium tested above 400 ppm.

Every 2 to 4 weeks  check and adjust TA and calcium before you adjust pH and shock. For the first few months do it every two weeks until you learn YOUR tub. If it stays fairly stable then you can drop back the testing to monthly.

Every 3-4 months drain, refill, balance the water, add the sodium bromide, shock, and put the bromine tablets back in.

Actually pretty easy!

If you follow these steps you will not need to waste money on defoamers, clarifier, enzymes, etc.!

The ONLY additive you might want to consider is a borate product. Borate has several benefits when added to a 30-50 ppm range. You can add borate with a commercial borate product such as Gentle Spa or Optimizer Plus or by using boric acid or borax. Most of the commercial borate products are a mixture of boric acid and borax to product a pH neutral product and might also contain a scent. Boric acid will slightly lower the pH but since the trend in a spa is a rising pH this should not be a major issue. If the pH is too low then add borax (at twice the dosing rate for pH up/sodium carbonate) to bring your pH into the 7.6 to 7.8 range, which is where your pH will want to 'sit' once the borate is added. Borax (both the decahydrate and pentahydate forms) will raise pH significantly and require the addition of either dry acid or muriatic acid to maintain the pH in the proper range. My recommendation is either boric acid or a commercial pH neutral product, Some commercial products are just the pentahydrate form of borax and will say in the dosing instructions that acid must also be added.

. To test borate I highly recommend the LaMotte borate test strips. They are much easier to read than the strips from Taylor, Hach, and AquaCheck. The Lamotte strips have color blocks that go from rose pink to tan while the others have color blocks that are (very close) shades of tan and very difficult to discern between them. Initially adjust borate to 50 ppm and test as often as you test your TA and calcium. If and when it drops to 30 ppm bring it back up to 50 ppm.

Hope this helps.

Chlorine is a bit cheaper than bromine but it really does require daily attention. Bromine (and what I described above is known as 3 step bromine and is the most forgiving) is not as fussy (acceptable pH range is wider and water balance is easier than chlorine or 2 step bromine) and really only needs attention once or twice a week after you get it set up, besides checking sanitizer level and pH before you enter the spa each time.

Happy bromine tubbing!

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