EI Dosing Levels

[bsagun]

Heres a comparison of APFUK advised starter kit dose levels and Clive's dose and 'Full' EI dose

View attachment 156631

Zeus.

Hi Zeus, this is a useful table, thanks.
I've been trying to calculate the concentration of nutrients i am currently adding (specifically Mg at the moment) due to issues described here. I am using APFUK starter kit with a reduced dose for a low tech tank.

As part of this i was effectively duplicating your table by working out the ppm of APFUK recommended dose, however, im coming up with different results. The result from the calculator is half what your table suggests. Am i using the calculator incorrectly, or are different assumptions being made between the two?

For example, APFUK dose is 3 times per week of micro/macro (ie 40ml 3 times a week in my 200l tank). From the calculator pic below, this gives 3.63ppm in a week (1.21*3). However, your table is almost exactly twice that, has your table calc assumed dosing 6 times per week perhaps?

Just trying to understand which one is right, or if im not using the calculator correctly.

Thanks

 

[Andy Pierce]

The calculator is correct, but it's also possible that the APFUK recommendations may have changed over time. If you go with the current 'starter kit' recommendation for a 500 ml stock solution of:

KNO3 (4 tsp)​

KH2PO4 (1 tsp)​

MgSO4-7H2O (6 tsp)​

you wind up with weekly concentrations of:

K 13.4 ppm​

NO3 17.7 ppm​

PO4 5.5 ppm​

Mg 3.6 ppm​

By the very nature of EI dosing, you shouldn't have to be radically concerned by the exact values and almost any version of EI dosing will be "good enough", but that being said I can't resist messing with it so I actually use (the APFUK recommendations in parentheses):

KNO3 (4 tsp) -> 3.5 tsp​

KH2PO4 (1 tsp) -> 0.5 tsp​

MgSO4-7H2O (6 tsp) -> 8 tsp​

K2SO4 (0 tsp) -> 5 tsp​

which does:

K 24.6 ppm​

NO3 15.5 ppm​

PO4 2.8 ppm​

Mg 4.8 ppm​

plus whatever comes along for the ride with the SCAMBS local water supply (which they claim is 30 ppm NO3; no figures given for any of K, PO4 or Mg).

 

[bsagun]

Thanks for the reply Andy. Agree try not to get too hung up on specifics, really just want to compare the ppm between what i've been dosing and other regimes. I think some of it might be using the teaspoon measure and it's assumed weight, which unsurprisingly can vary. I've just found the brilliant IFC Calculator where all the units are in grams, so might have to get a digital scale to make sure im comparing like for like with the calculator.