[Delphinus]

Well, weirdness abounds. Looks like yesterday's readings are suspect after all.

I tried testing again today and got 13ppm. I tested my other tank and it was the same as it's ever been at 5ppm.

So, just for giggles, I tested the water in the reactor with the pellets, and noticed something odd. If I tested by putting water into the sample vial, I would get readings anywhere from 13 to 19 (did 4 tests in a row all with different numbers). If I tested by putting the probe into the reactor itself, I got steady readings of 7 again and again. So I thought (not initially putting two and two together), oh, ok, something in the tank is spiking the nitrate, but at least the reactor is doing its thing and reducing the nitrate.

But then I tested my sump without the sample vial, and got 7. So I tested the main tank and again got 7. Back into the vial, I got 13, 14 and other numbers.

Soooo .. I guess my testing is being thrown off by interference. I don't know if it's the syringe I'm using to collect 5ml of tank water, or the probe's sample jar itself that's causing the interference. It bears mention that I rinse the probe and the vial itself with tap water after every use before I put it away, so I don't think it's any residual left on the probe itself. Also weird that the 40g tank has steady readings of 5. Just for giggles I should see what reading I get if I just stick the probe in the tank water in that tank (I didn't think to try that tonight..)