Ammonia is at 0.2ppm. . . what could be the cause?

[r.reefer]

My mixed reef tank has been running for almost 2yr. I noticed when I tested my water this week that my ammonia was 0.2. The image I attached is of my RODI water, because I wanted to see if there was any ammonia in IT too. I just got these RedSea testing kits this week, and I can’t for the life of me tell if it’s 0.2 or 0. I think it’s 0.2, but I wanted to see what others on here thought. If it’s 0.2 even in my RODI water, what should I do? I just replaced the cartridges a few months ago. I also used my old API test kit to test my aquarium water (not RODI), and it read the ammonia as 0.

 

[melonheadorion]

That's more toward 0 than it is .2. You also have to keep in mind that you then have to do the conversion for total monitoring, so you're less.than .02

 

[Uncle99]

Either something big died, many small things died, or you have a bad test kit.
2 year old mature tank would show zero, always IMM.
Try another test.