I am hoping to find a few people in the forums familiar with the hydrobuddy software.

I am a complete neophyte to hydroponics and nutrient calculators. My son and I recently built a rain tower. http://www.tomorrowsgarden.net/content/rain-tower-vertical-hydroponic-system

We are also using HydroBuddy v1.5 to make our nutrient solution for our tower. After mixing everything together the TDS meter readings are twice as strong as I expected.
(The TDS meter was calibrated last night with a 1500 NaCl solution)

In the HB program we selected formulation recipe (Tomato Howard Resh)

We selected 2 liter stock solution.
We selected concentration factor of 100

Since I wanted about 5 gallons for my reservoir.... I mixed 18 liters (4.75gal) of final solution by adding 180ml of part A into the 18 liters and mixing well. Then adding 180ml of the part B into the same 18 liters that I had mixed the part A into. After mixing well... the TDS meter displays 1850 PPM or (EC 3.6 mS/cm). This is almost exactly twice as strong as the prediction from hydrobuddy program. It predicted 900PPM or (EC of 1.8 mS/cm).

Per the instructions in the program: ((("Values calculated for the preparation of 2 liters of A and 2 liters of B solution. Please use 10mL of A and B within every liter of final solution.")))

I interpret this as saying: 10ml of A added to 1 liter of water, then add 10ml of B to the previous liter of water that contains A. So I end up with 1.02 liters (1020mL of solution that contain 1000 ml of water, 10ml of A and 10ml of B.

Was I supposed to mix 10ml of A into 1 liter of water.... then mix 10ml of B into a separate 1 liter of water... for a total of 2.020 liters of final solution? When I do this ... the PPM (EC) is as predicted in the software.

Someone please tell me where I went wrong.

Thanks,
Marty - aka SCFalconry.

Our ingredients are as follows:
Part Name Formula Grams
----- ------ ---------- ---------
A - Iron EDTA Fe(EDTA) 7.691
A - Calcium Nitrate (Tetrahydrate) Ca(NO3)2.4H2O 155.023
A - Potassium Nitrate KNO3 169.047

B - Manganese Sulfate (Monohydrate) MnSO4.H2O 0.492
B - Phosphoric Acid (85%) H3PO4 37.822
B - Zinc Sulfate (Dihydrate) 35% ZnSO4.2H2O 0.057
B - Sodium Molybdate (Dihydrate) 39.5% 0.015
B - Copper Sulfate (pentahydrate) CuSO4.5H2O 0.055
B - Magnesium Sulfate (Heptahydrate) MgSO4.7H2O 101.42
B - Boric Acid H3BO3 0.343

Concentrations in PPM
----------------------------
N (NO3-) 209.344
K 327.153
P 50
Mg 50
Ca 131.537
S 66.525
Fe 5
Zn 0.1
B 0.3
Cu 0.07
Mo 0.03
Na 7.014
Si 0
Cl 0
Mn 0.8
N (NH4+) 0.9