Bromine to Dichlor

[Steelerpete]

I drained my tub a couple weeks ago to switch sanitizers and couldn't get the last inch or two of water out of the tub. So I filled the tub anyways and I have about a 400 gallon tub, I have some of my old Bromine stripes left over so I thought I would use them to measure PH and Alk and I noticed that I was getting a Bromine reading even though I'm using Dichlor. Is this because I didn't drain the tub right dry? Is this common? Or are the chemicals close in property's to give the reading? I also noticed that when I was on Bromine when I gave the tub a shot of granular Bromine it would show some free chlorine on the test strips I was using at the time that had Bromine/Free chlorine/ PH/and Alk. Any help would be great. :-/  

[TubsAndCues]

I drained my tub a couple weeks ago to switch sanitizers and couldn't get the last inch or two of water out of the tub. So I filled the tub anyways and I have about a 400 gallon tub, I have some of my old Bromine stripes left over so I thought I would use them to measure PH and Alk and I noticed that I was getting a Bromine reading even though I'm using Dichlor. Is this because I didn't drain the tub right dry? Is this common? Or are the chemicals close in property's to give the reading? I also noticed that when I was on Bromine when I gave the tub a shot of granular Bromine it would show some free chlorine on the test strips I was using at the time that had Bromine/Free chlorine/ PH/and Alk. Any help would be great. :-/  

Chances are good that you're fine.  Bromine and chlorine are very close chemically and you will very likely get false readings if testing for both.

[tony]

Chances are good that you're fine.  Bromine and chlorine are very close chemically and you will very likely get false readings if testing for both.

Yup, even though you are using bromine strips, you are actually measuring chlorine...and it works the other way too.

[Steelerpete]

Thanks for the info!!!!

[Dr. Spa™ Ret.]

Test strips don't measure chlorine or bromine...... They measure the oxidation potential of the water. Bromine strips then convert the "oxidation potential" reading  into a bromine ppm. Chlorine strips will convert the "oxidation potential" reading into a chlorine ppm. Bromine [chlorine] test strips will register the "oxidation potential" of chlorine [bromine], but their reading (color change) wont indicate anything understandable to you (other than there's something oxidizing in your water ). The test strips are specifically calibrated to the substance they're designed to test...... by the way, chlorine/bromine test strips will also register for non-chlorine shock (MPS).