Hydrochart is a free, browser-based Durov diagram maker. It projects the cation and anion triangles onto a central square to give water type, then extends the plot with pH and TDS panels for extra context. Everything runs locally; your data never leaves your device.
Make a Durov diagram in three steps
Load your data
Open the plotter and drop in a CSV or Excel file of major-ion concentrations, or paste a table. Column headers are matched automatically.
Get the diagram
Hydrochart plots the projected square position for each sample and fills the pH and TDS panels automatically — estimating TDS from the ions when it isn't supplied.
Export it
Download the finished diagram as vector SVG or PNG — sharp at any size, ready for a report, thesis or paper.
What a Durov diagram shows
A Durov diagram takes the cation and anion ternary compositions and projects them onto a central square whose position gives the water type — much like a Piper diamond, but rectangular. Its distinctive feature is the two extension panels: one for pH and one for total dissolved solids, so a single figure carries composition, acidity and salinity together. That makes it well suited to spotting processes like ion exchange or dissolution that shift type and TDS in tandem.
What data do I need?
Supply your major ions in mg/L and Hydrochart converts to milliequivalents and does the rest:
| Group | Ions |
|---|---|
| Cations | Calcium (Ca), Magnesium (Mg), Sodium (Na), Potassium (K) |
| Anions | Bicarbonate (HCO₃) and Carbonate (CO₃), Sulfate (SO₄), Chloride (Cl) |
| Optional | TDS, pH and EC — used for labelling and QA, estimated when absent |
Not sure of the layout? Download the CSV template and paste your values into it.
Why use Hydrochart
- Genuinely free. Create and view unlimited Durov diagrams with no account. Free exports carry a small watermark; Pro (USD $29/year) removes it and adds CSV export.
- Nothing is uploaded. The whole tool runs client-side in your browser, so confidential monitoring data stays on your machine.
- Publication-ready output. Vector SVG and PNG export, with drag-to-place sample labels and leader lines for clean figures.
- One dataset, every diagram. The same file also plots Piper, Stiff, Schoeller, Chadha, Durov and Gibbs — no re-entry.
- Built-in quality control. Every analysis gets a cation–anion charge-balance error, flagged when it exceeds ±5%.
New to Durov diagrams?
If you want the theory before you plot, read the companion guide: the Durov diagram explained. It covers what the plot shows and how to interpret where your samples fall.