I'm going through a little bit of a learning curve with my new spa, after 25 years we had to replace our old one. It didn't owe us anything. Said new spa came with an Ecopur mineral filter inside the pleated paper filter, and it said not to use Bromine with it. I think Ecopur uses Cu and Zn for mineral disinfection. I balked at replacing it with an Ecopur and instead purchased an inexpensive mineral sanitizer from eBay that I think is a copy of Nature2 (see attached photo). It's got some resin beads inside which I presume are impregnated with silver and/or Copper, and has worked well with the low (1-2ppm) chlorine levels I've been maintaining. I've had no clarity issues. It comes from China (I hate that, but the Nature2 probably does as well, probably from the same manufacturer). I've not been able to find information about this product to be able to determine if I can switch back to Bromine with it, and I never understood why the Ecopur was not supposed to be used with Bromine in the first place. Does anyone have any insight into this?