If I can trust the accuracy of the 20 ppm calibration solution which I prepared, my year old API test kit is way, way off, reading roughly 100 ppm. Is this possible? Thanks.
KNO3 Calibration Results
- Thread starter tackful
- Start date
Think I may be able to answer this one myself. Found a new API test kit in the back of my aquarium drawer (big mess in there!) and used my tank water as a basis for comparison w/older kit.
Results: 20 ppm vs 100+ ppm!
Had stopped dosing KNO3 based on erroneous readings of older kit. Maybe that's why the wisteria looks so awful.
Results: 20 ppm vs 100+ ppm!
Had stopped dosing KNO3 based on erroneous readings of older kit. Maybe that's why the wisteria looks so awful.
Big Bass
Banned
I knew i would learn something new here, i never heard of dosing potassium nitrate for plants, but then again ive never been able to grow anything but algae 
Interesting post thanks.
Interesting post thanks.
I just had the same thing happen. Compared a new kit to one that is about 5 years old. Not even close. One read about 20 and one easily over 80.
How did you make your reference solution? I would like to keep some solution around to keep an eye on my calibration.
It's not too difficult: mix 1 tablespoon of KNO3 w/1 liter of distilled water. Add 2ml of this solution to a fresh liter of distilled water and you have a 20 ppm KNO3 test solution. How to measure 2ml? The API test tube holds 5ml if filled to the line, so you can work it out from there.