De Meul · Fertigasie

Flowmeter Calculator

Multi-product tank · concentration-aware blended density
Rotameter dial · saturation-checked · error margin
Revises every dial DOWN, so tanks never run dry early
Water = 1.000 (factory default)
AMS runs cold (endothermic)
Max salt load per fill before splitting (cap 90%)
01

How the setting is derived

worked example · 4 t AMS in 20,000 L over 12.5 h

Step 1 · Rate to match run

Empty the whole tank across one revolution.

1,600 L/h
20,000 L ÷ 12.5 h = 1,600

Step 2 · Density correction

Float rides high in denser fluid. Correct upward.

×1.055 → 1,689
rate × √(ρblend / ρcal)

Step 3 · Safety derate

Revise down so the tank never runs dry early.

−5% → 1,605
set dial = 1,689 × 0.95

This is the fixed illustration behind every number the tool produces. The density-corrected rate (1,689 L/h) would empty the tank exactly on time — but the margin of error revises the dial downward, never up, because running out of product mid-pass leaves a strip under-fertilised, while finishing slightly late just puts the last litres on at the end. At −5% the safe set-point is 1,605 L/h, and the tank lasts ~13.2 h against a 12.5 h pass — a small deliberate overrun. Section 03 applies the same derate to every pivot; the tank builder at the bottom does it for any one-off mix.

How blended density is computed (and its limits)

Concentration-aware, per salt. Every salt carries its own density curve — density rises with concentration along a fitted slope, not a fixed factor. In a mix, each salt's density-excess over water is evaluated at its own concentration and the excesses are summed. So a salt at 400 g/L contributes nearly double the density lift it would at 200 g/L, and the model bends correctly across the range instead of pivoting around one point. AMS is verified exact at 100, 200 and 300 g/L; the honest residual is a fraction of a percent well past your working range.

Temperature. The model adjusts water density for your tank temperature and nudges the estimate accordingly. A cold AMS tank is denser, which pushes the float higher and the dial up — the safe direction.

What it still can't do. Salting-out — where one salt forces another out of solution earlier than either would alone — is ion-pair-specific chemistry with no clean general formula. The tool flags combined load risk conservatively (summed fraction of each salt's own solubility) rather than predicting an exact crash point. When the combined-load bar climbs, treat it as "test before you trust," not a precise limit.

Ground truth beats all of this. A weighed litre of the actual mixed stock (enter it in "Measured density" on the tank builder) overrides the whole model. And a bucket-and-stopwatch on the injection line sidesteps density entirely by measuring real litres/hour. Density correction is a prediction; the bucket is measurement.

02

Season programme — rates per hectare

edit any rate · every pivot gets the same kg/ha
Timing Growth stage Products (co-dosed in one tank) Stage total
Season total nitrogen
03

Per-pivot plan for a stage

mass scaled to area · fills sized to the tank
Fertigate pivots together — tick each pair sharing one tank & pump. The smaller pivot is slowed to match the larger's run; its speed setting is shown per pair (100% = full speed).
Spilpunt Area
(ha)
Tank
(L)
Run
(h)
Bagged mass
this stage (kg)
Fills
needed
Bags / drum
(500 kg)
Rate to match
run (L/h)
DIAL TO
(−5% applied)
N this
stage (kg/ha)

Bags / drum = how to load the bulk products (500 kg bags) across the pivot's physical 10,000 L drums, split as evenly as possible (e.g. 5/4/4 = 5 bags in drum 1, 4 in each of the others). Drums are drawn in parallel, so hydraulically they're one pooled tank — density, dial, and fills are computed on the combined volume. Bulk products round to the nearest 500 kg bag and every figure here uses that rounded mass; the N/ha column reflects the actual bagged amount, which lands within a few percent of the programme rate. Micro-nutrients are dosed loose (counted in density, not bagged). Fills needed = separate mix-and-run cycles if the pooled load would exceed the dissolve ceiling (90% of the tightest salt's solubility); the bag pattern shown is per fill. DIAL TO is the density-corrected rate revised down by the safety margin so the tank never runs dry early — set the float here.

04

Manual tank — one-off mix

for anything outside the programme

Use this for a corrective feed or any tank not driven by the season programme above. Add the products and mass you're putting in, and it returns the blended density, saturation check, and the dial for a chosen run-time. The programme planner (03) is the tool for your normal season passes.

Water you dissolve into
One revolution to empty the tank
Weigh 1 L mixed → overrides model
Total salt load
Combined conc.
Blended density
Total N in tank
Density-corrected rate
Set dial here (−5% already applied)
Empties tank in
Density source
Equal per hectare. Every pivot receives the identical kg/ha from the programme (02); tank mass = rate × that pivot's area, so a 64 ha pivot dissolves more total product than an 18 ha pivot but each hectare gets the same dose. Density is concentration-aware per salt; DIAL TO is the corrected rotameter reading. Fills respect each salt's solubility so you never try to dissolve more than the water can hold. The safety derate at the top is global and one-directional — it revises every dial down (never up) in the worked example (01), the planner (03), and the manual tank (04), so a slightly slow injection empties the tank a touch after the pass ends rather than running dry mid-circle.
N%: AMS 21 · Urea 46 · CaNO₃ 15.5 · micros & boric acid non-N. Solubility (g/L, ~20°C): AMS 750 · Urea 1080 · CaNO₃ 1290 · MnSO₄ 700 · ZnSO₄ 540 · CuSO₄ 320 · Boric acid 57.
Reminder: keep the tank recirculating — AMS is endothermic and runs cold; boric acid and CuSO₄ crash out first. Weigh a litre of mixed stock and enter it in the manual tank to override the density model; bucket-and-stopwatch beats all of it.