2 year old reefer 525 was doing great. nitrates were mid 20's so decided to dose nopox about same time my LPS were showing signs of stress. Long story short NOPOX was working but some LPS were slowly dying over weeks. Turns out my RODI was 0 TDS but my carbon and membrane were spent and i started to suspect chlorine breakthough so i dosed alpha. It worked and corals started to perk up. So i did two 30% water changes and voila... corals that were still alive came back strong so my RODI was contaminated.. i can only assume chlorine. Continued to nopox dose and then i had an ugly outbreak of something in my sand bed. I reduced NOPOX for a week and no luck. The lowest i got with nopox was 8 nitrate and i had to dose some phosphate on occassion but never bottomed out. I thought is was cyano so i tried chemiclean and didn't touch it. Now i am afraid its dinos . Before i buy a microscope was wondering if this was an easy ID? I am afraid i did a lot of damage to my bacterial population with bad rodi. I stopped NOPOX and have now been dosing microbacter7 every day for a week hoping to restore my bacterial population.