Bala shark has red around his fins

I don't I was just guessing because when I tested it it wasn't quite at 0.5 but it wasn't at 0 either. The color didn't match either one it was more in between so I made a guestimation.
 
The lowest liquid ones I've seen goes to 5 ppm...that low of NO3 sounds unlikely unless your tank is very understocked, you have a lot of plants, or you have some sort of denitrification going on like a DSB.

Are you sure that you didn't confuse that with nitrIte (NO2)? I'm just curious. Glad the problem went away.
 
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