Nitrates not registering?
I just mixed my first batch of KNO3 solution per chucks calculator and added enough to raise my 75 gal aquarium to 5 ppm nitrates from 0 ppm. (In the past I have been using the botanica nitrogen fert by Kent) After doing this I waited a few hours and checked the nitrates again with my seachem nitrate test kit that has been working fine all week. The nitrates were still zero I added the same dose 3 more times while measuring a few hours after adding each dose. It started to read the nitrate but at very low levels. One of the fish began acting stressed out (breathing at the surface) so I did a 30% water change. The fish is back to normal now. I ordered another seachem test kit today as I think this must be the problem. I don't have any ref solution left so I can't check the kit today. I do remember somebody giving a formula to make some ref soln. Has anyone one had a similar experience and does anyone know how to make the ref soln.
Thanks in advance!!