Testing bromine levels after a shock treatment

[brandonc]

I'm new to maintaining a hot tub. I've also built the top myself, which was a it's own journey and a story for another time.

I sanitize with granulated bromine, and some slow dissolve bromine tablets in a floater. My pH is in spec.

I've shocked my tub with a non-chlorine shock three times since I got it back up and running a few weeks ago. I'm shocking based on the product advice, which says to apply it every 5 to 7 days. When I apply the shock, the brome levels test very high for a few hours. I test with a Taylor hit. I understand the initial high reading to be normal. What happens next, I don't know what to make of. For about a day, sometimes more, the test will indicate total bromine to be at the highest level which is 10-20ppm. Sometimes the color even looks darker than the scale. Then after a few seconds the test sample will lighten up and then stabilize.

Which reading do I trust? Do I trust the reading immediately after adding the reagents and mixing the sample, or the one after a few seconds pass? Is it possible I don't need to add as much shock as the instructions say? Do I not need to shock at all, or perhaps adjust my sanitization schedule and method?

 

[JoyfulNoise]

Which Taylor kit are you using and which reagents for testing? Are they the pink DPD reagents or the yellow OTO reagents?

 

[brandonc]

I am using the Taylor K-2005 kit. The reagents make a pink color are DPD R-0001 and R0002.

 

[JoyfulNoise]

I am using the Taylor K-2005 kit. The reagents make a pink color are DPD R-0001 and R0002.

Ok. Those test reagents will bleach out above 10ppm FC or 22.5ppm bromine. What you’re seeing is the color go deep pink/red and then bleach out back to a lower value. You can’t measure shock levels that high. As well, any residual MPS will add to the total oxidizer level.

If you want to measure bromine levels that high, then you need a different Taylor kit. Specifically the FAS-DPD titrating reagents as well as the MPS interference removal reagents.

 

[brandonc]

Ah, OK. Thank you. Well does that mean I'm shocking the water incorrectly? Since it's bleaching out, that means to total bromine is way higher than it needs to be for several days.

 

[brandonc]

I do leave the cover off after shocking for as long as I can, which is 8 hours before I have to lock it up over night. From what I read, if things are going correctly, the bromine level should drop to normal within a couple hours hours. I feel like I might be doing something wrong.

 

[JoyfulNoise]

Can you please post more history on the tub, fill out your signature, tells what chemicals you are using (exact brands help). We really can't help with diagnosis without good information. Bromine can be tricky and it depends a lot on what you are using and what make/model hot tub you have.

 

[brandonc]

OK, I've put some information into my signature.

I put 650 gallons of water into the tub 3 weeks ago. I use it about once a day. I shower before entering the tub. It's in a shaded area.

The water details prior to my shock treatment today:
ch 200
tb 2
ph 7.4
ta 100

I've been using Spa Guard products. Non-chlorine shock (sodium dichloro-s-triazinetrione) Slow dissolve bromine tablets, bromine granules, pH increaser, pH reducer, stain and scale control, phosphate remover, water clarifier.

I've been adding water clarifier, stain and scale control and phosphate remover weekly as instructed by the products.

The pH has been kept in the range of 7.4 - 7.6.

I've been topping off the bromine tablets weekly.

I've been shocking weekly as instructed by the product.

 

[JoyfulNoise]

OK, I've put some information into my signature.

I put 650 gallons of water into the tub 3 weeks ago. I use it about once a day. I shower before entering the tub. It's in a shaded area.

The water details prior to my shock treatment today:
ch 200
tb 2
ph 7.4
ta 100

I've been using Spa Guard products. Non-chlorine shock (sodium dichloro-s-triazinetrione) Slow dissolve bromine tablets, bromine granules, pH increaser, pH reducer, stain and scale control, phosphate remover, water clarifier.

Let's save you some money and headaches. Start by reading this Sticky -

How do I use Bromine in my spa (or pool)?

Originally Posted by waterbear There is a lot of misinformation on the proper way to use Bromine so I hope this primer is helpful. First, you need to establish a bromide reserve in the water. Bromine tablets can do it by themselves but it can take literally weeks until enough dissolves. Some...

www.troublefreepool.com

FYI - Dichlor (sodium dichloro-s-triazinetrione) is NOT non-chlorine shock. It is very much chlorine shock. Non-chlorine shock is potassium monopersulfate (MPS).

I've been adding water clarifier, stain and scale control and phosphate remover weekly as instructed by the products.

In a properly maintained hot tub, none of those chemicals are needed at all. Clarifier will just serve to gum up your filters, scale control is unnecessary unless you have detectable metals in your fill water or high calcium hardness. Being in Summerville, MA (I used to call it SlummerVille when I lived there during my college days ... perhaps it has gentrified by now ...), I doubt you have high mineral hardness but iron could possible be an issue. Phosphate removers are also totally useless in a hot tub as algae is rarely an issue.

The pH has been kept in the range of 7.4 - 7.6.

This is fine, but a bit on the low side. With your higher than recommended TA, pH rise is caused by the off gassing of CO2 (from carbonate alkalinity). If you lowered your TA and let your tub operate between 7.6 - 8.0 pH range, you'll find that your pH is more stable and the rate of pH is a lot less. Sanitizing bromine is not as affected by pH as chlorine is, so it's very effective throughout the entire 7-8 pH range.

I've been topping off the bromine tablets weekly.

I've been shocking weekly as instructed by the product.

Brominating tablets by themselves, if they are primarily BCDMH (bromo-chloro-dimethyl hydantoin) do not need activating with shock. The chlorine part of the BCDMH activates the bromine. But they are acidic and, with long term use they will depress TA and lower pH. You really don't need pH increaser which is usually soda ash (sodium carbonate) as it strongly raises both pH and TA. You could simply hold your TA constant using baking soda (sodium bicarbonate ... yes, Arm & Hammer baking soda that you buy in the supermarket to make cookies with ...) and that will support your pH. Aeration from the tubs jets will provide the needed pH boost as carbon dioxide is outgassed.

Does your tub have an ozone generator? If so, it could be adding to the oxidizing of the bromide back into bromine thus causing your high bromine levels.

One final note - ALL HOT TUBS, new or used, should be purged with a plumbing biofilm remover. Everyone on TFP uses Ahh-some as it is hands down the best biofilm remover out there. After an initial purge, tubs should be re-purged every 6 months to one year depending on use. You can search "Ahh-some" on this forum for all the testimonials you need and the company owner, @Ahhsomeguy , is regular contributor to this forum and very helpful hot tub dude. @RDspaguy is the go-to guy for all questions related to hot tub mechanicals and and repairs.

Read the sticky and feel free to ask questions.

 

[brandonc]

Let's save you some money and headaches. Start by reading this Sticky -

How do I use Bromine in my spa (or pool)?

Originally Posted by waterbear There is a lot of misinformation on the proper way to use Bromine so I hope this primer is helpful. First, you need to establish a bromide reserve in the water. Bromine tablets can do it by themselves but it can take literally weeks until enough dissolves. Some...

www.troublefreepool.com

FYI - Dichlor (sodium dichloro-s-triazinetrione) is NOT non-chlorine shock. It is very much chlorine shock. Non-chlorine shock is potassium monopersulfate (MPS).



In a properly maintained hot tub, none of those chemicals are needed at all. Clarifier will just serve to gum up your filters, scale control is unnecessary unless you have detectable metals in your fill water or high calcium hardness.

OK, it figures the chemical company would tell you to use more chemicals. Ya, I had found that thread a little while before you replied. I like the idea of using regular supermarket liquid bleach as my oxidizer.

Being in Summerville, MA (I used to call it SlummerVille when I lived there during my college days ... perhaps it has gentrified by now ...)

Yes, Slumerville is VERY expensive to buy into now. Thankfully I bought 15 or so years back. It's cleaned up a lot, to the point of being boring. Hah. I'm ready to move on soon.

, I doubt you have high mineral hardness but iron could possible be an issue. Phosphate removers are also totally useless in a hot tub as algae is rarely an issue.

The water is very soft here. I had to add quite a bit of calcium after the initial fill.

I had been using phosphate remover because my phosphates were approaching the a level that I was told one does not want. I'm wondering if this is because my tub was getting littered on by a tree. Though I've just put a canopy over it this week, so maybe that'll solve the problem if that was the source.

This is fine, but a bit on the low side. With your higher than recommended TA, pH rise is caused by the off gassing of CO2 (from carbonate alkalinity). If you lowered your TA and let your tub operate between 7.6 - 8.0 pH range, you'll find that your pH is more stable and the rate of pH is a lot less. Sanitizing bromine is not as affected by pH as chlorine is, so it's very effective throughout the entire 7-8 pH range.

My water chemistry is what it is because I was given a spa-guard recipe to build up the chemicals based on the water chemistry of the fresh fill. Most literature I have tells me to keep the pH between 7.4 and 7.6, including the products. I'm new, so I'm following the instructions as best I can, but maybe they aren't the best instructions. Though I have seen sources saying that a pH a bit out of this range is OK too.

Brominating tablets by themselves, if they are primarily BCDMH (bromo-chloro-dimethyl hydantoin) do not need activating with shock. The chlorine part of the BCDMH activates the bromine. But they are acidic and, with long term use they will depress TA and lower pH. You really don't need pH increaser which is usually soda ash (sodium carbonate) as it strongly raises both pH and TA. You could simply hold your TA constant using baking soda (sodium bicarbonate ... yes, Arm & Hammer baking soda that you buy in the supermarket to make cookies with ...) and that will support your pH. Aeration from the tubs jets will provide the needed pH boost as carbon dioxide is outgassed.

Well, my hot tub is homemade. I never added an aerator. I was attracted to basic water circulation because it's smoother less noisy, and the water holds heat a bit longer. Though I could add one, and you've pointed out a practical reason to have one that I wasn't are of. I'll send some photos if you are interested. I could not buy one, at least one that I wanted in the time frame I wanted because of the market demand for hot tubs. I had the ability to get the parts that mattered, and to build an insulated basin, so I did that. I did buy a manufactured spa-cover though.

Does your tub have an ozone generator? If so, it could be adding to the oxidizing of the bromide back into bromine thus causing your high bromine levels.

No ozone generator.

One final note - ALL HOT TUBS, new or used, should be purged with a plumbing biofilm remover. Everyone on TFP uses Ahh-some as it is hands down the best biofilm remover out there. After an initial purge, tubs should be re-purged every 6 months to one year depending on use. You can search "Ahh-some" on this forum for all the testimonials you need and the company owner, @Ahhsomeguy , is regular contributor to this forum and very helpful hot tub dude. @RDspaguy is the go-to guy for all questions related to hot tub mechanicals and and repairs.

Read the sticky and feel free to ask questions.

OK, it looks like I can setup a purging scheduling outside of the freezing winter months, which is great!

So in my situation, what am I to do about the high, or rather unmeasurable bromine levels? Am I to keep taking the cover off until I get a proper reading, and then once I do starting adjusting the chemistry per your instructions and then alter my bromine and shock treatment per the post you have pointed out?

 

[JoyfulNoise]

Your phosphates may be high because your municipal supplier is adding orthophosphate to control for metal corrosion and lead ... given the age of the water systems back east, lead soldered cast iron piping is quite common. That said, phosphates really don't matter to a hot tub. They have no chemical reaction with the sanitizer. In a swimming pool, or any body of water, phosphates are a growth nutrient for algae. But given that hot tubs really aren't that susceptible to algae and given the fact that you have a very effective sanitizer against algae growth, trying to control phosphates is not that big a deal. You could measure your fill water (Taylor sells a decent test kit for phosphate) and then add a dose of phosphate remover at start up to get it to near zero then not worry about it anymore until you refill again. If you do use a phosphate remover, buy the one from SeaKlear or Orenda as they as commercial grade phosphate removers that are highly concentrated and they do not add anything else like clarifiers or "magic minerals".

Your bromine levels should come down with time. Definitely leave the cover off and let some UV light get to it. Then try to follow the bromine regimen in the sticky. You really do not need to overdo it with shock or activation of the bromide bank.

And really, seriously, a pH anywhere between 7.0 and 8.0 is fine to soak in. It is one of the biggest myths of the recreational water industry that you need to keep water in some tight pH range. It's is simply not true ... your body is quite capable of handling a wide range of pH and the chemical sanitizer you are using works the same no matter if the pH is 7.0 or 8.2 or anything in between. Another myth is that you need some magical amount of calcium in the water. For a hot tub, all you need is enough calcium hardness to destabilize bubble/foam formation and that happens around 50ppm CH or so. Anything more than that is unnecessary. I personally like the feel of very soft water as I grew up with it but now live in a place where the water coming out of the faucet is like concrete slurry. Also, check in with your municipal water report and see what's on the list ... it's probably fine because they have to follow EPA regulations but you never know what interesting elements on the periodic table you might find ....

 

[brandonc]

Thank you for the advice.

Is there a target bromine ppm one should aim for when shocking a tub? I waited two days for the bromine test to read acceptable for bathing after I applied the last treatment. I'm just wondering if I'm overdoing, and maybe I don't need to add as much chemical as I think. I'm going to try using bleach tomorrow as the post you recommended suggests.

 

[JoyfulNoise]

Thank you for the advice.

Is there a target bromine ppm one should aim for when shocking a tub? I waited two days for the bromine test to read acceptable for bathing after I applied the last treatment. I'm just wondering if I'm overdoing, and maybe I don't need to add as much chemical as I think. I'm going to try using bleach tomorrow as the post you recommended suggests.

Any reading above 20ppm is considered shock level for bromine. You might try to aim for that by creeping up on it slowly. Add half what you normally would and then test after 15mins of circulation.