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Originally Posted by mos90  OOOOOOPS!!! im at 80ppm tooo. not good. looks like another water change tonight. dam these test kits. now i have to rethink kno3.... |
I've been using API kits for over a year and my experience is that it is not reliable when used as directed.
I suppose that this is not practical for most people but I still use the kit following some good lab practice.
You have to run your sample with at least these three controls.
Your high limit say 20 ppm.
Your low limit say 10 ppm
A blank run with distilled water
If you run your test with a high and low level control you will have a high level of assurance that your sample is OK.
I do not use the color chart that comes with the kit. I have a spectrophotometer; so I compare the absorbance of the 20 ppm and 10 ppm controls with the sample. Using this method I am certain of my NO3 level to +/- 1 ppm.
I've been running the test this way for a long time and have found that control absorbance changes from kit to kit. This means that when you compare your sample to the color chart your answer will change depending on the kit you have. In recent kits I've discovered that you need to use 2x the amount of reagent #2 to get good adsorbance readings. (Even with shaking it for more than one minute).
Actually, getting a local club to buy a spectrophotometer would make a hugh improvement in the ability of participant to get accurate and reliable test results. You can buy a good used Spec. for about $100 - $200.
Just my rantings rtp
Re: dosing ei no3 levels still low at the end of the week. 
Hybrid Mode
