TDS AND Chlorine

Bugger · Jun 9, 2015

Can chlorine get threw a TDS meter undectected. Or will it give a value

AquamanE · Jun 9, 2015

I South Florida they use choloramines. TDS read Zero. Many of my corals suffered by either STN or no color.

Bought a choloramine test kit and found the culprit. Added a choloramine filter to my ro/di the change was instant after a few water changes.

Bugger · Jun 9, 2015

I thought so. So many people trust those silly things

Randy Holmes-Farley · Jun 10, 2015

A good carbon block filter will break down chlorine and chloramine, but the TDS meter is not intended to measure anything uncharged. The TDS meters are intended to measure how effective the RO membrane and DI resin are functioning. If you want to detect chlorine you need a kit.

On this specific question of whether chlorine is detected, the answer is complicated. Chlorine as pure Cl2 will not be detected by a TDS meter, but in tap water it partly dissociates into other forms, including chloride and OCl-, both of which are readily detected with a TDS meter and are removed by a DI.

AquamanE · Jun 10, 2015

Randy Holmes-Farley said:
A good carbon block filter will break down chlorine and chloramine, but the TDS meter is not intended to measure anything uncharged. The TDS meters are intended to measure how effective the RO membrane and DI resin are functioning. If you want to detect chlorine you need a kit.

On this specific question of whether chlorine is detected, the answer is complicated. Chlorine as pure Cl2 will not be detected by a TDS meter, but in tap water it partly dissociates into other forms, including chloride and OCl-, both of which are readily detected with a TDS meter and are removed by a DI.

Randy- mine ran through Ro/and DI with zero TDS yet when i tested for choloramines it was very evident that it was there.

Yes, I then changed my carbon blocks and it was no longer detected, but the fact that it was there after ro/di has made me very paranoid.

dbl · Jun 10, 2015

AquamanE...can I ask where you purchased the chloramine test kit. I've been unsuccessful in my search. Found plenty of chlorine tests.

Randy Holmes-Farley · Jun 10, 2015

Fwiw, any chlorine kit will detect chloramine. You only need a chloramine kit if you wan to distinguish it from ordinary chlorine. I use and like the Hach chloramine kit.

Randy Holmes-Farley · Jun 10, 2015

AquamanE said:
Randy- mine ran through Ro/and DI with zero TDS yet when i tested for choloramines it was very evident that it was there.

Yes, I then changed my carbon blocks and it was no longer detected, but the fact that it was there after ro/di has made me very paranoid.

FWIW, I was only referring to chlorine, not chloramine,which does not dissociate the same way into charged species.