Thanks for so rigorously showing this! Any chance you plan to test the nitrate checker?
Here is the test of the LR Nitrate Checker...Have not done the HR
Hanna low range nitrate accuracy, nitrite interference
Dan's being modest. He was filtering zinc out of the red sea NO3 test to improve color formation at least a couple of years before hanna's kit said we should. Sometimes I think he DIY's all his own tests, and just buys hobby kits to check his work. :p it's an impressive amount of color...
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