I cleaned the media in my eheim 2026 two days ago. I rinsed the mech. noodles in tap water also the blue sponge. I replaced the white pad with a new one. The bio-tray was very dirty and this is where I made a big mistake. I gave it a quick rinse in tap water not submurged just a four second spray. I think I killed off my bacteria,as the next day all of my fish were struggling to breathe. I didnt associate this with my filter as I had been making major water changes the past three days to lower nitrate. I had added baking soda and epson salts to increase ph. and kh. and I thought the fish were suffering from ph. shock. I changed 75 percent of my water immedately. I then tested for ph. =6.8 , kh.=17 amm.=0.0. I got a big suprised when I checked nitri and it was 20. I then decided the fish were shocking out from nitrite poisoning. I went to lfs and bought boi-spuria in an effort to jumpstart my bio-filter. I lost two large rubens a full grown masons peacock a yellow tailed acei and a two year old lions cove.The remaining six fish are still not right breathing a little heavy. nitri. is still high. I hope I dont wake up to six more dead fish. Is there anything I can do now to lower nitrites? Dave Spada [email protected]