There are no "standards" provided with the kit. When I tested the water from my marine aquarium, currently running the full AquaForest system, with the kit, the results indicated expectedly low levels of both nitrate and phosphate. Without the standards, I can't confirm that this is correct (but it probably is). So, most likely this kit does what it claims (i.e. accurately measures low levels of phosphate and nitrate in seawater).
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