Hello I finished building my koi pond halfway through July. I filled it with tap water and treated it with the Aquascape Detoxifier. The Tetra Test Strips told me that the tap water had 3 ppm of nitrite, this seemed kind of high so I went and bought the Seachem MultiTest Nitrite & Nitrate. This told me that my tap water actually had around .25 ppm of nitrite. I added the Aquascape Starting bacteria and finally put my koi in there around August 8th. I didn't have too much free ammonia because I used the Aquascape Detoxifier to bind the free ammonia. Last week the Seachem test started showing some nitrite however it was less than .01 ppm (Barely showed). However at the end of last week the nitrite started to go up to around .5 ppm. I started adding salt (Morton Blue Bag Salt). The Nitrite kept going up. The Seachem Test shows the nitrite level to be 5 ppm if not higher. I raised the salinity level to .15%, I've doing 13% water changes however the Nitrite level won't go down. My koi don't seem to go up to the surface and gasp for air like I've read that some do when they have brown blood disease. The water I put in, I treat with the Aquascape Detoxifer and also add enough salt to bring the salinity level to .15% before adding it to the pond. The pond dimensions are (8 ' x 10' x 5 ' (deep)). It's around 1400 gallons because of some granite boulders in the pond as well as it's in a weird shape. I have 5 Koi (2-12", 1-11", 2-9"). As of right now one 12" koi is not in the main pond and is in the quaratine tank due to a head injury. I am new to this so I would really appreciate if someone could help me out and tell me how I can go about lowering my nitrite levels to a safer level. I posted this same a little bit ago however I made a mistake and accidentally said I finished building the pond halfway through August when I meant July, I couldn't find it so I just thought I would post this again. Thank you