I was just thinking that yesterday when I noticed that my vegging plants were looking underfed at 5g/gallon. 5g is probably no longer 5g at my RH even though the bag is only open for a minute or two each morning. I've gone to 5.5g now and the plants seem happier.Cool! 1st thing I'd do is get a decent idea of how much it takes for a gram before you open and close the bag a lot. It wicks up moisture quite easily so 1/2 teaspoon when it's fresh will weigh less than if it's exposed to a bunch of humidity later on. I found 1g to be equal to 1/8 tsp of powder. From that point on I didn't weigh it anymore, I went by volume.
I separated my bag into three when I got it, so I may test this bag against one of the other ones using a level teaspoon.