Dichlor additions converting to Bromine?

[Whitepine459]

Hi all, new spa owner, 5 y.o. Hot Spring SX, previous owner said he used bromine.

Drained the tub, transported it, cleaned it with vinegar (minor scale present), rinsed and filled. (Will do a de-gunker soon during first drain.)

Decided to go with N2 method, with daily additions of dichlor.

So far so good. TA is good, pH is good. When I test after 20 mins of adding, FC looks good at ~2-3ppm.

Hours later, without bathing, I'm seeing the FC drop right off and the total bromine at "normal" levels (~5ppm I think)

I think I read somewhere that this will happen if you straight switch from bromine to dichlor.

I'm guessing there was some bromine water in the pipes that didn't get fully drained.

Is this an issue with my sanitizing regime? Anything I should do now or watch for? Switch to daily MPS?

Thanks

[The Wizard of Spas]

Lots of ways to do this and a lot of smart people will undoubtedly chime in with helpful hints and tips, so I'll just address one aspect of your question and leave the more-able contributors to chime in on other facets of your query. . .

I hope I am not speaking out of turn here, but generally when going the mineral-based route, it is to reduce the amount of Di-Chlor used.  MPS (Potassiumperoxy Monopersulfate) is the oxidizer used to help eliminate all the contaminates not named algae or bacteria.  Therefor, when you do use Di-Chlor, it only has to kill algae/bacteria (as it is the only EPA-registered sanitizers to do so), and thus you use a much smaller amount, and that smaller amount is much more effective since the rest of the contaminants are already gone.

Doesn't mean you shouldn't use Di-Chlor daily, and there are those that take it to the next step and monitor Cyanuric Acid levels by pivoting to bleach after a spell.  Lots of ways to do this.   But as you are asking, I'd just switch to MPS to limit the need for di-chlor.

Just one guy's opinion however, and I am sure you'll get even more quality insight very soon from other posters.  Good luck moving forward!

[Whitepine459]

Thank you for the thoughts, much appreciated

(The reason for using the dichlor daily is mainly cause I don’t have pure MPS, just a 50-50 MPS-dichlor product and pure dichlor. Thought I’d keep it simple and use the dichlor daily and the other for shock. Plus I have the means to test for FC but not for MPS at this time.)

So perhaps I’ll try to find some MPS and a means to test it.

Regarding the FC to bromine thing:

I’m now wondering if my standard test strips are misleading me. I now suspect that the “total bromine” colour test on my kit can also indicate “total chlorine”, based on another kit I came across. Mine just doesn’t show the TC scale as well.

If that’s the case, looks like when my kit says TB=5, it could be that my TC=3.

Could that be true?

I.e. my strips look just like these, except the TB/TC scale only reads “TB” https://www.amazon.com/AquaChek-541604A-Select-Strip-Swimming/dp/B00B784ULY

[Jacuzzi Jim]

 My guess is your test strips (the bromine sq) is being fooled by the chlorine.  Since bromine comes from chlorine it is possible.    You want something simple take a look at the @ease product.   I am currently testing it in my own spa and have been very happy with it.  Bullfrog is offering the same thing only a different delivery system.  I know hot spring is as well..

 I am using this as mine is an older Jacuzzi. 

 https://www.yourpoolstore.com/products/spa-frog-ease-floating-sanitizing-system?variant=24560009857&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=EAIaIQobChMIrtGo673P4AIVMRh9Ch2e3gWYEAQYAyABEgKPLvD_BwE

[bud16415]

If you flushed it and all that I don’t think you have residual bromine converting your dichlor.

I use a 99% dichlor product and convert to cleaning bleach when the sanitizer reaches 30-50 PPM as time goes on and it drops I switch back to dichlor. My tub around 400 gallons with normal use needs about 1 tablespoon of dichlor per day. When I switch I use 1/3 cup of bleach. If we don’t go in it for a day I will skip adding any and I check it from time to time using a Clorox brand 6 in 1 test strip. I found those the cheapest and they check the most.

I don’t use the non chlorine shock daily I go by look and hopefully not smell when to use it. depending on usage I add about a capful once a week. The water looses its sparkle and I know when it needs it.

The only drawback I have found to this method is it requires you to do something every day. It takes a minute or two and I do it after we get out in the evening. If we are going away for more than a few days I switch it to @ease in a feeder.