My trident np is a week old now. The nitrate test np vs Hanna are close. 8.9np vs 9.7 Hanna. Now the phosphate is not even close. .03 np vs .13 Hanna. I tried calibrating the np. That made it worse. I ended up resetting it. It still reads low compared to Hanna. I did the Hanna 3 times and was within .01 each test. Now the np reads .06 and Hanna is .14. Anyone have experience with the trident and how to overcome this? I was going to calibrate with my tank water but need to get it back under .1 before the np with allow it.
I am not sure where you got that information. The "calibrated" aquarium water range is:
Nitrate 50 ppm
Phosphate 0 - 1 ppm
As long as you are within those ranges you can manually calibrate. Also note when you calibrate using your tank water and favorite test kits you need to do collect a pint of water from the same area the NP is sampling from. You use this water to run 4 to 5 (up to you which) manual tests for both Nitrate and Phosphate, remove any outliers, then average the remaining results. Those are what you will use to test. Once that is done you take the NP sample line, place it in the remaining water, and finish the calibration. This way both manual and NP are using the same water.