I mentioned about a 10 or so years ago, we found about 1-4ppm per day of uptake in a planted tank. Many at the time vigorously questioned this range.
Some still do.
Mark from Monterey Bay Aquarium measured some surge uptakes of 8ppm per day of NO3 in some of their tanks.
Per gram of plant, wet weight vs dry weight also makes a huge difference when comparing these rates.
Per gram of plant biomass is the fair comparison, some folks/hobbyists like to suggest that their tanks are all are on equal terms when it comes to plant biomass(they discuss their tank as a whole, not as a function of per gram weights), when clearly, even a novice can see that, they are not.
Still, most folks will do this, but species, the scape design(open layout vs dense jungle etc) and biomass really can and do vary greatly.
That's the way I used in my research and in the latest installment of the BarrReport to use for comparisons.
I've not seen any aquarists, and few companies other than SeaChem, and Tropica do this.
So this begs the question: what are they really comparing(myself included) when they state such rates?
They should compare more and report a range, rather than 1.5 ppm per day etc.
If all you have is one system and are not willing to deviate much in the routine , then it's really hard for you to compare to other systems.
Many of us on the APD were very wary of this years ago, today, few even consider it on the forums.
Do not believe everything you think.
Regards,
Tom Barr