Describe the plant here: flow rates, tank sizes, paddle speeds and hydraulic loading rates. Enter what is on the plant's design drawings, or what SCADA says it is running at; the tool does the conversion.

Behind the scenes the tool works out the mixing intensity (G) at each stage, then the jar paddle speed that gives the same intensity in a 1 L jar. That is what makes the bench test a meaningful copy of the plant.

It does the same for the clarifier rise rate and the filter rate. All of these become bench settings on the next steps.

No plant data, or just exploring? Pick Typical values below and set the jar mixing intensity directly on the Jar mixing step.

This step tells you what to dial into your jar tester. The tool has worked it out from the Plant match step: the boxes headed Set jar tester to are the numbers you set on the bench, paddle speed (rpm) and how long to run each stage.

The target G and stage times are filled in from your plant data. Only change them if you deliberately want to test different mixing; most people never do.

If one of those boxes turns amber, the speed is outside what a jar tester can do (over about 250 rpm or under about 10). That usually means the paddle dimensions in Setup do not match your bench paddle.

This tab gives you the recipe for each stock solution you'll dose from. There are four of them:

• Coagulant stock — a diluted version of your plant's neat product, made at a strength that gives you syringe-friendly volumes (a few mL per jar).
• Polymer stock — 1 g of polymer made up to 1 L with deionised water, aged 30 minutes before use.
• Acid stock — for lowering pH (typically 0.5 N sulphuric acid).
• Base stock — for raising pH if you need to (sodium hydroxide or sodium carbonate).

The tool tells you exactly what to weigh out (or measure with a pipette) and what volume to make up to. Make coagulant and polymer stocks fresh each day — they age and lose strength.

The simple rule: 1 mL of a 1 g/L stock added to a 1 L jar gives 1 mg/L dose. Everything else scales from there.

The default SG and % active for every coagulant product, and the default polymer stock strength, are in Settings (top right) and apply to all tests. Changes made on this step apply to this test only.

This is where you decide what each jar gets. The auto-fill buttons fill a ladder to suit the test you are running. Change one thing at a time so the results can be read.

Typical sequence:

1. Coag dose screen first — hold pH constant, vary coag dose across the jars.
2. pH optimisation next — at the best dose, vary pH around the suspected optimum.
3. Polymer trial last — at the best (dose, pH), test polymer addition.

About acid and base doses: The tool can estimate how much acid (or base) you need to reach a target pH, using the raw water alkalinity from the Results tab. Click Estimate acid/base to populate the columns. The estimate accounts for the alkalinity that the coagulant itself consumes, but it's a starting point — not a precise prediction. Always measure the actual pH of the first jar and adjust your dosing accordingly. If you don't enter raw alkalinity, the columns stay empty and you'll need to set the volumes manually based on a pre-titration.

During the flocculation phase, watch each jar and note the floc size class at each timepoint. The size chart below is your reference card — match what you see in the jar to a class number.

Two things that make the observations reliable:

• Same method every time. Hold the jar against a white background with even overhead light — floc looks bigger in shadow and smaller in glare. Any operator can do the sizing; what matters is that everyone uses the same background, lighting and reference chart.
• Look in the bulk of the jar, not at the surface or against the walls. Floc concentrates near the top meniscus and looks bigger there than it really is. Ideally, observe while the paddle is still turning slowly.

Floc behaviour tracks faster than any analytical result, and weak or slow-forming floc is usually the first sign that the chemistry isn't right.

This is where the analytical numbers go. There are two samples to measure from each jar:

• The clarified water (what you drew off the top after settling), and
• The filtrate (what comes through the jar filter paper, simulating the plant filter).

The tool shows whichever columns make sense for your plant — both if you're doing clarification + filtration, just one if you're doing clarification only or direct filtration.

What to measure:

• Turbidity — always. Clarified turbidity tells you how well the floc settled; filtrate turbidity tells you how well the filter is polishing.
• Organics — pick one parameter (UV₂₅₄ absorbance, True Colour, DOC, or SUVA) and measure it on both clarified and filtrate. Turbidity alone isn't enough for a proper assessment.
• pH and alkalinity — read on the clarified water, before any chlorination.
• Residual metal — total in the clarified, dissolved in the filtrate.

When picking the optimum jar, don't just go for the lowest number. Check that the dose one step lower is nearly as good (it's cheaper), and that the floc looked robust in your observations. A flat plateau is more reliable than a knife-edge.

Three ways to take your work away, all from this step:

• PDF report: to print and take to the bench, or send to a colleague. Choose the sections below. In the print dialog pick Save as PDF, and turn off Headers and footers for a clean page.
• Spreadsheet (CSV): the dose ladder, observations, results and floc strength data as tables.
• Project file: a complete copy of the test (setup, plant, doses, observations, results). Open it later to carry on, or send it to a colleague using this tool. Opening a file replaces the test on screen, so save first if you want to keep it.

This is a follow-on test that answers a question the standard jar test can't: how robust is the floc? You make the floc, take a size reading, then shear it hard for a short burst, take another reading, let it reform, and take a third reading.

Two chemistries can give the same clarified turbidity but behave very differently downstream. Weak floc shears in the filter inlet and packs tightly at the surface, giving fast headloss rise and short filter runs. Floc that can't reform after a shock will punch through the bed and cause early turbidity breakthrough. Strong, reformable floc rides through flow swings and dose drift without complaint.

The tool gives you two numbers:

• Strength Factor (Sf) — how much of the floc survived the shear. Higher is stronger.
• Recovery Factor (Rf) — how well the broken floc reformed. Higher is more forgiving.

Run this to compare two coag/polymer combinations that look equivalent on clarified turbidity, to verify a polymer actually toughens the floc, or to diagnose filter breakthrough.