Just Starting With Bromine

[bartman9]

We finally got our Jacuzzi J365 installed and I could use a little help with balancing the water. I followed the 3-step Bromine process outlined in this forum, but not perfectly. The Taylor K-2106 test kit did not come until today and we couldn't wait that long to use the hot tub. So I tried to balance it using the test strips the tub came with... bad idea, I know.

Anyway, this is what I did:

- I used baking soda to bring the TA up to about 100.

- Then I used borax to raise the pH to 7.5

- I added 1 packet (2 oz) of Leisure Time Sodium Bromide. My tub has 400 gallons of water in it.

- I added 2 ounces of 6% bleach (just realized this was a mistake, it should have been 8 ounces)

- I added a floater with 4 bromine tabs in it.

All of the above was done on Friday... now it is the following Monday and I just receive my K-2106 test kit. Here are the measurements I have taken:

Alk: 130 ppm

pH: 8.0

Calcium Hardness: 140 ppm

Bromine: 0

Since I realized I didn't add enough bleach, three days ago, I just added about 6 ounces of bleach. Here is my updated Bromine reading:

Bromine: 2 ppm

Now that I have my test kit, I want to make sure I do things right going forward. I would appreciate any suggestions on what I should do next to get things more balanced.

Thanks,

Dave

[chem geek]

Your pH is on the high side, probably due to the high TA. Bromine is still effective at high pH so that's not a problem, but you want to avoid scaling. I would have targeted more like 80 ppm for the TA. Even with bromine tabs, which are net acidic, spas tend to rise in pH due to aeration from jets and from the hotter water which outgasses carbon dioxide faster. You can just adjust pH by adding acid and over time the TA should drop.

Adjust your floater's output so that you are able to maintain a background bromine level, usually around 4 ppm, in between soaks. After each soak, add around 5 fluid ounces of 6% bleach (or 3.6 fluid ounces of 8.25% bleach) for every person-hour of soaking. If you have an ozonator, then you'll add a lot less, but it sounds like you don't have an ozonator.

[bartman9]

Thanks for the help, chem geek!

I will use dry acid to try and bring down the Alk and pH later today. Then I will use the bleach to try and bring up the Bromine.

I do have a question about the floater with Bromine tabs in it. How many tabs should I put in there? I currently just put 4 in, but it was a complete guess.

Thanks,

Dave

[arches2]

use your acid demand test in the taylor kit to get your ph down to 7.2-7.6 (it will go back up some from your TA too high). Keep doing this until your TA is 60-80. You will find the sweet spot over time and time is the only way you will find what works for your tub and chemicals. I HIGHLY suggest adding 50 ppm borax as it makes ph super stable. I can honestly say the only time i ever add acid is during startup when i put the borax in. The ONLY chemicals i need to maintain my tub are baking soda, bromine tabs (acidic hence the ph and TA drops), and bleach (plus my start-up chems).

As far as the number of tabs you need, it depends on your floater type. if it's a flooded floater (not the best) like mine, i've found about 4-5 with the floater closed almost all the way works for me but i have a low bather load (1 person 3-4 nights a week for less than a half hour). the best floater option out there is the pentax that chem geek recommends as it doesn't flood all the tabs.

[bartman9]

I thought Borax will raise the pH? Isn't a pH of 8 already too high?

I do have the recommended floater.

Dave

[chem geek]

He meant 50 ppm borates. You can add that either by a combination of 20 Mule Team Borax with acid (either Muriatic Acid or dry acid) OR by adding boric acid such as with Proteam Gentle Spa. The borates act as an additional pH buffer but without the side effect of carbon dioxide outgassing that causes pH to rise.

[bartman9]

A couple of things and an update...

- I do have a 400 gallon Jacuzzi J365 which has their Clearray system which uses UV-C technology. Don't know if that is just marketing hype of actually helps me in any way.

- I did add dry acid to bring down the pH.

Now for the latest readings:

Alk: 70ppm

pH: 7.6

Calc Hardness: 120ppm

Bromine: 1.25ppm

- Since I do have this Clearray UV thing, how how high should I bring up the Bromine by adding bleach?

- From the earlier post it sounds like I should add Borax and Dry Acid to help buffer my pH. Is that correct? Any recommendations on how much to add?

I appreciate any help you can offer!

Thanks,

Dave

[chem geek]

I suggest you just set up your bromine spa first. Follow the instructions in Bromine for Beginners. If you find that with your use of bromine tabs that your pH is still tending to rise, then if you end up lowering your TA you can then add the 50 ppm Borates. It's best to do one thing at a time and minimize what you need to add since you might not need a lower TA and having borates. With bromine tabs that are net acidic, the pH may be reasonably stable at your current pH.

As for the bromine level, the UV system doesn't do anything to pathogens that can grow on spa surfaces (i.e. that don't circulate through the UV system) so it doesn't change the required bromine background level.

[bartman9]

Oh, I think I get it now. The UV cuts down on the amount of oxidizer (bleach) I need to add to maintain 4ppm of bromine. The bromine level we want is the same, but the amount of bleach needed is decreased. Is that right?

[chem geek]

Well, UV isn't a complete oxidizer the way that ozone (and some hydroxyl radicals from its breakdown) is, at least for some parts of bather waste. You'll just have to see if it actually does end up cutting down the amount of bromine tabs and bleach you end up needing to use. You can experiment by having it off vs. on over periods of time to compare, assuming you can turn it off and on. UV is more commonly used for indoor pools to control chloramines and is used in commercial/public pools as a way of killing the protozoan oocyst Cryptosporidium parvum.

[canTub]

Well, UV isn't a complete oxidizer the way that ozone (and some hydroxyl radicals from its breakdown) is, at least for some parts of bather waste. You'll just have to see if it actually does end up cutting down the amount of bromine tabs and bleach you end up needing to use. You can experiment by having it off vs. on over periods of time to compare, assuming you can turn it off and on. UV is more commonly used for indoor pools to control chloramines and is used in commercial/public pools as a way of killing the protozoan oocyst Cryptosporidium parvum.

While I was running Dichlor/Bleach I tested the effect of my UV system several times (by turning it off). I noticed a significant difference in required maintenance (CC buildup). With the UV I could leave my FC very low (1ppm) and many times at 0 for half-days without building CC. Without the UV, I would notice CC buildup very quickly if I let the spa drop to 0 FC.

One comment though is that my UV system is on a 24-7 circulation pump circuit.

I'm one week in on Bromine now, once I get a stable setup I'll play with the UV again to see the effect. I have to say that I'll definitely be switching back to Chlorine once the weather warms up (and I can do daily maintenance without freezing to death) though. My wife and I absolutely hate the smell of Bromine on our skin (and I'm keeping it at 1-2ppm).

[chem geek]

Yes, that make sense because it takes chlorine some time to oxidize CC so if you don't use enough (usually after a soak) then CC will form, FC get to zero, and stop there. The UV can oxidize (technically, break apart into radicals) the CC. So for something like ammonia that would need 1.5 chlorine for every ammonia to fully oxidize it, it takes 1 chlorine for every ammonia to form CC (monochloramine) that then the UV can break down at that point. So somewhat less chlorine would be needed, but probably not reduced as much as by ozone, if the bather load is heavy.

[bartman9]

I ended off adding Borax to keep the pH more stable. With my 400 gallon tub, I added 22.6 ounces volume of Borax and 10.1 ounces volume of dry acid. With that done, here are my new readings:

Alk: 60ppm

pH: 7.4

Calc Hard: 130ppm

Bromine: 7ppm

Do all of these seem to be in order? Should I make any adjustments?

I was playing with the Taylor Water Balance Calculator wheel that came with my test kit and it says my Saturation Index is -0.4, which is says may be corrosive to concrete, plaster or metal surfaces (below -0.3). Should I be concerned about this? Should I bring the pH up to be more balanced?

Thanks,

Dave

[chem geek]

You're in good shape. Don't worry about the saturation index. You don't have any plaster or exposed grout surfaces. Metal corrosion doesn't come from a low saturation index. Low pH is much worse for metal (and for vinyl, such as with vinyl pools), but your pH is fine.