For those who tend towards these errors you can always premeasure the daily doses into small vials. I have a ton of little brown glass bottles and fill all my bottles at once with the bulk fert powder for the macros. I dose micros straight from the bottle since it is just one powder. Prepacking prevents errors, it also works for people who take alot of meds and has been shown to reduce med errors. Now my problem is that i forget whether I dosed micros or macros on the previous day. pretty soon I will need one of those day of the week pill planners for my ferts.