Yet another EI dosing Q!


Junior Poster
Aug 29, 2005
Just trying to get my head around ppm using the Fertilator....

Have I got this right:

If I dose according to the suggestion in Tom's article for a 20G high light tank, this is:

1/4 teaspoon of KNO3 3-4x a week (every other day) equates to 10ppm NITRATE, 6.6ppm POTASSIUM per dose


1/16th-1/32nd teaspoon of KH2PO4 3-4x a week (every other day)

Say I use 1/32nd amount then this equates to 1.6ppm PHOSPHATE, .66ppm POTASSIUM per dose.

Do I just add up the amounts to get the total ppm per dose? and is that enough potassium?

If I use Seachem Equilibrium how do I calculate how much Ca, Mg, and K I am adding? On the bottle it gives concentrations as percentages e.g. Ca 8.06%.

I know I might not need to know how much in the Equilibrium if I put enough in, but I'm nosy! I like knowing these things :)

Thanks for any help,


Tom Barr

Staff member
Jan 23, 2005
Re: Yet another EI dosing Q!

Try emailing SeaChem directly, they changed their K+ formulation some. I use it like I would K2SO4 although it adds less K+ obviously.

If you follow the recommendations, the K+ should come out close to NO3. And over time and if you address the 03 and go molar ratios N:K, we see that K+ is in a huge excess relative to ratios and plant needs.

The leveling off of K+ will be higher than N since less is needed by the plant over time(see the graphs for EI as they progress through time).

Basically less K+ is used relative to N in the dosing routine.

Tom Barr