Wait, what? Combined bromines aren’t measured like CC?

[Malka]

I’m the caretaker for 2 spas in NYC.
~1200 gallons each
Use bromine tabs/liquid chlorine
CH 225
pH 7.2-7.5, creeps up to 7.8, lowered with liquid muriatic acid
95* F

I’ve been chugging along for 15 months with my tf-100 (with refreshed reagents). Somehow I missed that combined bromines aren’t measured with r-0003


My spas have been very clear lately. The only problem I have is the number I was getting on the fas-dpd for CC is 2-2.5
Is that a concern at all? Is that really 5+ppm combined bromines?

I’ve been keeping the sanitizer at the upper range 5-6ppm because that has been keeping the water really clear.

I’d rather not do a refill, even partially, unless it’s necessary.

Post in thread 'How can i check my combined bromine in a spa'
How can i check my combined bromine in a spa

 

[JoyfulNoise]

Time to drain and refill.

You can not measure combined bromine compounds with a DPD test kit. The DPD indicator dye does not distinguish between sanitizing bromine or combined bromine, both of those cause the indicator to change to a pink color as soon as you add it. You can only measure total bromine (free plus combined).

If you are doing the second part of the test where you add the R-0003 drops and the sample is showing 2.0 to 2.5 ppm, then you also have combined chlorine compounds as well or other trihalomethane (THM's) compounds. In other words, you hot tub water is full of disinfection by-products (DBP's) that negatively impact human health. It's not healthy to soak in a tub with those levels and, if this tub were inspected by a health department, it would be shutdown immediately.

Unfortunately, there is no way to fix the issue chemically, you simply have to drain and refill the spas. This is the primary problem with running hot tubs/spa's - they are very high bather load small volumes of water which means they get fouled very quickly from human use. Think of it like a bath tub - when you fill up a bath tub and use it, the water by the end of a soak is pretty cloudy and nasty. You spas are simply big bathtubs with filters and sanitizer on them to extend the number uses you get out of the water. But, eventually, all bath tubs must be drained.

It's pretty much a given that a single family household can get about 2-3 months out of a regularly used hot tub before the water needs to be changed. That amount of time shrinks as the number of users and frequency of use goes up.

 

[Mdragger88]

the only thing you can test for is total bromine- there’s no separate test.
You just wasted some r0003
* - edited to add after @JoyfulNoise ’s post -
People are generally instructed not to even use the r-0003 in a bromine situation- does this mean that they should be?

 

[JoyfulNoise]

No concern- as stated by chemgeek- the only thing you can test for is total bromine- there’s no separate test.
You just wasted some r0003

Not true. If the OP is doing the test and there's CC's showing up, those a DBP's and the tubs need to be drained. The OP is using both liquid chlorine and bromine tabs. Bromine tabs also contain chlorine. CC's are forming in the water from the chlorine in the LC and tabs. The CC's will not go away very easily on their own.

 

[JoyfulNoise]

If you really can't drain the tubs, then you can try to shock the tubs using non-chlorine shock (MPS or potassium monopersulfate) to see if the CC's levels decrease. The only problem is that MPS can show up as CC's and give confusing results. So you'd have to shock the tubs and then wait several days to see off the CC readings you are getting go down. MPS can be very acidic and so you have to also monitor pH and TA to make sure you don't crash the tub pH while shocking.

As I said, there's no really easy chemical method to get rid of persistent CC's in a hot tub. They simply build up over time from use. The easiest solution is to drain and refill.

 

[Mdragger88]

Not true. If the OP is doing the test and there's CC's showing up, those a DBP's and the tubs need to be drained. The OP is using both liquid chlorine and bromine tabs. Bromine tabs also contain chlorine. CC's are forming in the water from the chlorine in the LC and tabs. The CC's will not go away very easily on their own.

I have edited my post- this poses the question of should folks be instructed to perform the cc’s test on occasion in a bromine situation? If so the sticky should be updated to include this information.

 

[JoyfulNoise]

the only thing you can test for is total bromine- there’s no separate test.
You just wasted some r0003
* - edited to add after @JoyfulNoise ’s post -
People are generally instructed not to even use the r-0003 in a bromine situation- does this mean that they should be?

I have edited my post- this poses the question of should folks be instructed to perform the cc’s test on occasion in a bromine situation? If so the sticky should be updated to include this information.

No. There's no need. Hot tubs should be regularly drained to avoid all of these issues.

In a bromine tub, the sanitizer levels, and sometimes the presence of ozone in certain tub models, is typically good enough to avoid these types of issues especially when tub is regularly drained, purged with Ahhsome, and refilled. Using R-0003 would simply confuse the owner as it's not specific enough to give good advice with. In a purely chlorine sanitized body of water, CC's can be measured. When one is using bromine along with chlorine, the CC value becomes harder to understand. It really just comes down to good water management which means periodic and regular draining.

 

[Malka]

Thanks!

I want to try the MPS idea, but I don’t have any on hand. I guess I’m changing water.

I’ll run the cc test only if I haven’t changed the water in a month or so. Just to keep an eye on it.

Really appreciate your help.

 

[bikerdan]

Interesting. I was just about to post about this same thing. I just barely switched from a Chlorine tub to Bromine. Drained, flushed, and refilled 4 days ago. I’m using the 3 step method. I’ve been trying to get my floated dialed in so I’ve been testing a lot. I decided to run the CC part of the test just for the heck of it. I’m getting about 1-2 ppm on that part of the test. So I’m confused. Should I get a CC reading that soon after changing water?

 

[JoyfulNoise]

Interesting. I was just about to post about this same thing. I just barely switched from a Chlorine tub to Bromine. Drained, flushed, and refilled 4 days ago. I’m using the 3 step method. I’ve been trying to get my floated dialed in so I’ve been testing a lot. I decided to run the CC part of the test just for the heck of it. I’m getting about 1-2 ppm on that part of the test. So I’m confused. Should I get a CC reading that soon after changing water?

Are you activating bromine from a bromide bank using liquid chlorine OR are you using brominating tablets ?

Did you purge your plumbing using Ahhsome?

 

[bikerdan]

Started first day with Brominating Concentrate cause I didn’t have pure Bromide. Next day I got the pure Bromide and put in recommended amount for the bank. I have a floater with Bromine Tabs and I’ve used bleach and MPS as oxidizer to get bromine to correct levels and after soaks.

 

[Ahhsomeguy]

Hi JoyfulNoise: Have you noticed that on numerous occasions when a direct question is asked regarding purging and draining the hot tub that many of those who ask questions seem to avoid answering your question as to whether they did perform a purge and drain? Many hot tub owners simply hate to drain their tubs.

 

[JoyfulNoise]

Started first day with Brominating Concentrate cause I didn’t have pure Bromide. Next day I got the pure Bromide and put in recommended amount for the bank. I have a floater with Bromine Tabs and I’ve used bleach and MPS as oxidizer to get bromine to correct levels and after soaks.

Between the brominating tablets supplying both bromine and chlorine (and dimethylhydantoin), the liquid chlorine, and MPS, it's no wonder the tests are confusing. All of those are potent oxidizers which will cause the DPD indicator to turn pink. The MPS can also show up on the DPD test as CC's. Chlorine can create both sanitizing bromine as well as chloramines that would show up on the CC side of the test. And, if the tub has not been properly purged with Ahhsome, you can have all sorts of nasty disinfection by-products being generated inside the plumbing.

Generally speaking, this entire thread is a testament to just how complicated spa and hot tub care can be and why it is so important to follow basic guidelines. First, all tubs and spas, no matter their age, manufacturer or bather load, should be regularly purged with a biofilm remover. TFP recommends Ahhsome because of the actual data that exists which shows it does exactly what it says it does and surpasses all other spa purge products on the market. Aside from that, Ahhsome has been used by almost every member of TFP that has a hot tub and their testimonials are uniformly positive with regard to how Ahhsome works. Aside from plumbing purges, the other aspect of good hot tub care is regular and periodic water exchange. It really can't be emphasized enough but Taylor Technologies said it best on their website -

"Hot tubs ARE NOT just small swimming pools!"

That statement is 100% true. You can not treat a hot tub the same way you treat a swimming pool. The temperatures, bather waste concentration, disinfection/sanitizer chemistry, and exposure of the the tub water to the atmosphere are all radically different than a residential swimming pool. As such, hot tubs simply need to be dumped regularly just as you do not reuse bath water indefinitely. There's only so much sanitizers and oxidizers can do to keep the water quality in good control.

My suggestion to anyone using bromine as their sanitizer is to simply ignore doing the CC part of the test and keep track of water quality. If the water quality seems off, then dump the tub and start over. It makes little sense to fight (and waste money on) keeping a few hundred gallons of water clean for months or years. Dump it and move on.

 

[bikerdan]

Thanks for responding. Unfortunately it sounds like we really don’t know what causes the CC reading when using bromine. As I said above, the tub was drained and flushed. It was also only refilled a few days ago. Anyway. Again. Thanks for your time and expertise in these things. They are super complicated!