# RE: PMDD Dosing

PMDD Dosage Calculations

Having just gone through this exercise, I thought someone else could use it
also.
From the "original recipe" in "Control of Algae in Planted Aquaria" by Sears
and Conlin

Chem        Vol     Mass (g)      K       N       S      Mg      Fe      Mn
B      Zn      Cu      Mo

K2SO4       2 tsp         14    0.45            0.18

KNO3        1 tsp          6    0.39    0.14

MgSO4+7H20  2.5 Tbsp      33                    0.13     0.1
CTEM        1 Tbsp         9                                    0.07    0.02
0.013   0.004   0.001  0.0006

Elemental Mass (g)              8.64    0.84    6.81     3.3    0.63    0.18
0.117   0.036   0.009  0.0054
Daily Dosage in (mg/L)         0.864   0.084   0.681    0.33   0.063   0.018
0.0117  0.0036  0.0009 0.00054

The daily dosage was calculated by

dd = x / s * d * 1000 (mg/g) / t

where

x = elemental mass (g)
s = solution volume (ml)
d = daily volume (ml)
t = tank volume (L)

From the paper a good starting place for iron is

dd = 0.63/300*3*1000/100 = 0.063 mg/L

I am currently using chemicals from Homegrown Hydroponics and my recipe for
my tank is
(note that the densities of some of the chemicals are different)

Chem        Vol     Mass (g)      K       N       S      Mg      Fe      Mn
B      Zn      Cu      Mo

K2SO4       2 tsp         14    0.45            0.18

KNO3        1 tsp          7    0.39    0.14

MgSO4+7H20  2 Tbsp        30                    0.13     0.1

CTEM        1 Tbsp        12                                    0.07    0.02
0.013   0.004   0.001  0.0006

Elemental Mass (g)              9.03    0.98    6.42       3    0.84    0.24
0.156   0.048   0.012  0.0072
Daily Dosage (mg/L)           0.5178  0.0562  0.3682  0.1720  0.0482  0.0138
0.0089  0.0028  0.0007  0.0004

The daily dosage was calculated by

dd = x / s * d * 1000 (mg/g) / (t * 3.875 (L/gal))

where

x = elemental mass (g)
s = solution volume (ml)
d = daily volume (ml)
t = tank water volume (gal)

For example

dd = 0.84/100*1*1000/(45*3.875) = 0.0482 (mg/L)

Regards,
Harold.Walters at halliburton_com