I have 501 litres of water in my tank ie 130 US gallons approx.
EI dosing suggests 1.5 teaspoons in total weekly of to achieve 1-2ppm PO4.
I have KH2PO4. When i plug these figures in Fertilator i get 11.7ppm as PO4!!
Who is correct?
LAKA

That is total, not per dose.
Divide that into 3 and you get about 3-4 ppm per dose
You do not need that much, 6-7ppm per week is plenty.

So divide a teaspoon into 3 parts.
That should be enough per dose.

1/3 tsp 3x a week

EI does not suggest a target 1-2ppm based on that amount, the 1-2ppm is a min amount, not a max amount that's maintained under heavy growth/uptake etc

The actual dose that is really suggested is about .4 of teaspoon per dose or about 1.2 tsp over an entire week.
About 9 ppm per week or 3 ppm per dosing, 1 ppm or so is removed pretty quick, then leaves you with about 2ppm or more for the week.

I think most are fine with less..............but adding that much does no harm either.........

Regards,
Tom Barr