where do nitrates come from

[jtomasi1]

I use Poland Spring and have testing multiple times using the Salifert test kit. The tests have all come back with 0 Nitrates. Just a thought....

[SAW39]

Jawfish7777,
Nitrates (NO3-) are ions that dissolve readily in water yet also easily bind to organic compounds. The specific concern for our aquatic friends is that nitrates bind to the proteins of delicate organs such as gills. In my opinion, in low concentrations the effect is similar to a rash or other tissue irritation. In higher concentrations, nitrates are toxic by damaging gills and other surface tissues and by interfering with the immune system.