Tell the tool a bit about your bench and the plant you want to copy. There are three things it needs to know:
The defaults already in the fields are sensible for a standard Phipps & Bird jar tester with a 25 × 75 mm paddle — only change them if your bench is different. The tool does all the calculations for you in the background.
If you're new to the tool, populate it with a worked example to see how a fully-set test looks. When you're ready to do your own test, clear everything and start fresh.
This tab is where you describe the plant — flow rates, tank sizes, paddle speeds, hydraulic loading rates. You just enter what's on the plant's design drawings or what the SCADA tells you it's running at. The tool does the conversion.
Behind the scenes, the tool works out the mixing intensity at each stage — how vigorously the water is being stirred. It then figures out what jar paddle speed gives the same intensity in a 1 L jar. That's what makes the bench test a meaningful copy of the plant.
It does the same thing for the rest of the plant: the clarifier rise rate, the filter rate. All of these get translated into bench-scale settings on the next tabs.
If you don't have plant data — or you're just exploring — you can switch to Generic mode below and set the jar mixing intensity directly using typical values for a conventional plant.
Clarifier type doesn't matter for the jar test. What matters is the rise rate — the m/h that floc has to settle faster than to be removed. Set it from your plant's design or operating data.
For a meaningful filter step in the jar test, the tool needs the plant filter rate (to scale the analogy) and the media type (to pick a Whatman / membrane that mimics the bed cut-off). The jar test won't reproduce filter runtime — but it will give you a clean filtrate sample for analysis comparable to your downstream water.
This is where the plant settings turn into paddle speeds you'll actually use on the bench. The tool reads the mixing intensities you entered for the plant (rapid mix, each floc stage) and works out the RPM your bench paddle needs to spin at to give the same intensity in a 1 L jar.
You don't need to do anything here — just check the numbers look sensible. If you see an RPM higher than your jar tester can do (over about 300), or so low that the paddle won't actually move water (under about 20), the tool will flag it. Usually that means the paddle dimensions on the Setup tab don't quite match your actual bench paddle.
This tab gives you the recipe for each stock solution you'll dose from. There are four of them:
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.
This is where you decide what each jar gets. The auto-fill buttons populate a sensible ladder based on what test you're running — vary one thing at a time so the results are interpretable.
Typical sequence:
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:
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.
Edit midpoints in Settings if your bench reference differs. The chart on the right is rendered at on-screen scale — print the true-scale comparator from the Floc Strength tab when you need a bench card.
This is where the analytical numbers go. There are two samples to measure from each jar:
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:
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.
Four ways to get your work off the tool:
In the browser print dialog: set Destination to Save as PDF, and untick Headers and footers for a clean output.
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:
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.
PACl 10% Al₂O₃ medium basicity and Alum 14H₂O equivalent are flagged as Common in NZ.
Default SG and % w/v active for each liquid product. Override if your supplier's COA differs. Changes apply globally to new and existing tests.
Phipps & Bird standard: 25 × 75 mm. Per-test paddle dimensions live in Setup.
Used in Observations and Floc Strength. Edit the midpoints if your bench reference card uses different sizes.
A practical inventory of the gear you need to actually run a jar test. Brand examples are illustrative — equivalents are fine.
It helps you design, run, and report jar tests that actually represent your plant — whether that's clarification, clarification followed by filtration, or direct filtration. Behind the scenes it uses proper mixing physics (not rules of thumb) to translate plant conditions into the right bench paddle speeds, times, and doses. You don't need to do any of the maths — just describe your plant, set up your dose ladder, and follow the protocol.
Every mixing process — your plant's rapid mix, your plant's floc tanks, or a jar on the bench — can be described by a single number: the mixing intensity. The tool works out what that intensity is at each stage of your plant, then figures out what jar paddle speed gives the same intensity in a 1 L jar. It does the same translation for the clarifier (matching rise rate to settle time) and the filter (matching filter rate and media).
v2.6.