HydroBuddy is a completely free and open source program for the calculation of nutrient solutions for hydroponics and general agriculture built by me – Daniel Fernandez – based on my experience in hydroponics as a professional chemist. This piece of software was coded from the ground up using the Lazarus open source programming suite and implemented using appropriate database solutions as well as a powerful linear equation solving algorithms from AlgLib. HydroBuddy is available for Linux and Windows. HydroBuddy is released under the GPL license. For Linux or Windows installers are included. You can also use on MacOSX if you compile from source.

Screenshot of the “Main page” tab of the HydroBuddy hydroponic fertilizer calculator

These are some of HydroBuddy’s features :

Calculates the weights of specific substances needed to arrive at specified concentrations of different elements (formulation to salt weights calculation)

Easily fine tune your salt weights after calculations.

Contains library with commonly available fertilizer salts (new in v1.7)

Raw salts in the included DB have links to help new users know where to buy them (accessible by clicking the salt name in the results tab). Please note these are amazon affiliate links that support the development of the software. (new in v1.7)

Includes ability to save and load lists of substances used for calculations. (new in v1.7)

Empirical model for the prediction of EC (new in v1.8)(read more here)

Calculations in ppm, mmol/L, mol/L and meq/L.

Calculate liquid additions in mL and add any custom substances as liquids

Edit the percentage elemental composition of each substance or add new ones to fit your needs

Powerful open source linear equation solver provided by AlgLib

Always tries to find the best mathematical fit to a formulation by a given group of substances

Allows to get the concentration values for the addition of a certain specified amount of substances (salt weights to formulation calculation)

Easy-to-use interface for the addition, edition and assignation of substances to calculations

EC prediction module based on an empirical mathematical modification of a calculation based on limiting molar conductivities

Use the resulting weights of a formulation calculation to perform a calculation of the opposite nature and vice versa (easily allows you to see the effect of manual modifications)

Calculations for both direct additions and A+B concentrated solutions

Use any custom substance as a part of an A+B concentrated solution calculation

“Copy Commercial Nutrient” module which allows you to copy the ppm results of a commercial nutrient formulation

Water quality module allows you to include water quality analysis within the calculations

Adequate implementations of instrumental and gross errors with custom instrument precision input

Proper database implementation allows you to easily save your custom formulations

Set default water quality and data log data sets that load automatically on program startup

Save and load formulations using any concentration unit.

Choose between grams or ounces

Choose between liters, gallons and cubic meters for volume inputs

Export calculation results to a CSV file

Tutorial tabs showing and explaining the main features of the program !

The program allows anyone to easily carry out calculations for the preparation of nutrient solutions, a very cumbersome task that can take a lot of time and effort when done manually. If you’re having trouble with HydroBuddy and you would like to purchase support please email me by using the contact form with your requirements to receive a quote. If you are using HydroBuddy for academic purposes please cite its use as follows:

Daniel Fernandez, “HydroBuddy: An open source nutrient calculator for hydroponics and General agriculture”, v1.8, url: http://scienceinhydroponics.com , 2020 You can download the program through the following links:

Just unzip the program and run the hydrobuddy.exe file.

Unzip, then make sure you execute “chmod +x hydrobuddy” within the folder so that you can execute the program.

Note for MacOS users: MacOS won’t allow you to open Hydrobuddy correctly unless you compile it yourself. To do this you’ll need to build HydroBuddy on your own MacOS computer. Install the Lazarus IDE and then compile the HydroBuddy project from source. Please note that the software is provided “as is” (no support available for free). If you want to get a support quote please contact me via the website’s contact form.