Plant Care
- • Climate Control & VPD16
- • Disease & Pest Management14
- • Nutrient Solutions & EC34
- • Plant Health Monitoring7
Inputs
10 parameters · live recalculation on every change
CM
50cm
200cm default
500cm
CM
30cm
100cm default
300cm
CM
20cm
50cm default
200cm
CM
10cm
30cm default
100cm
Pro Settings — Lab Controls
°C
10°C
20°C default
35°C
%/DAY
0%/day
5%/day default
50%/day
Advanced Settings — Deterministic Corrections
CM
0cm
100cm default
500cm
MM
12mm
19mm default
50mm
Insight band · live
From usable volume to the total reservoir
The usable water the system needs, topped up by headroom — the running total lands on the reservoir you have to build.
- Usable volume 600 600.00 L
- + Headroom 400 1,000.00 L
- Total volume 1000 1,000.00 L
Pump flow: 333 GPH
Turnover: 1.8 /hr
Running total after each term — the final net matches the headline reading in the result card, kept in sync live.
Deterministic model
10 inputs · 10 outputs
Runs 100% in your browser
This is a deterministic model: the same inputs always produce the same outputs, calculated entirely in your browser with nothing sent to any server. It is a planning aid — not a quote, not a dosing instruction, and not a yield forecast. Treat every line as a working estimate and validate it against your own prices and measurements.
It models one system: The Pro-level sizing and sanitation blueprint for a hydroponic reservoir. Enter tank dimensions, working depth and head lift and the engine returns the gross and usable litres, the pump flow after the turnover duty, leak and lift multipliers, the head-corrected delivery against the pump curve, the ebb-and-flow flood time, pipe-line velocity, the exact hypochlorous acid dose from a 500 ppm stock, a temperature-aware C×t sterilization contact time, and a root-rot safety grade wired to your reservoir temperature and sanitation line.
What the Reservoir Volume & Dosing Engine — Volume, Flow & Sterilization Blueprint returns
The engine computes 10 outputs from your 10 inputs. The headline number is Total Volume (L), alongside Usable Volume, Pump Flow, Head-Corrected Flow. Every output updates live as you change a parameter.
What it does not do
Outputs depend on the inputs and assumptions shown here. Confirm relevant measurements and local conditions before acting.
STEP 01
Measure the reservoir length, width and height in centimetres and the working fill depth, leaving 15–25% headroom so root and media mass never overflow.
STEP 02
Compute the gross litres — L × W × H ÷ 1000 — and the usable litres scaled by the working depth fraction.
STEP 03
Pick the system turnover duty (DWC 1×, NFT and Dutch bucket 2×, ebb-and-flow 4×) and size the pump with the head and leak multipliers applied.
STEP 04
Check the delivery against the rated pump curve — head derates output toward the max-head ceiling — and confirm the line velocity stays in the 0.5–1.5 m/s band.
STEP 05
Dose the sanitation: ≥2 ppm active HOCl from a 500 ppm stock, 50–100 ppm peroxide, or a UV-C lamp sized at ~1 W per 40–50 GPH, and hold the temperature-adjusted contact time.
STEP 06
Grade the root-rot risk from temperature and the active sanitation line: green ≤22°C sanitized, yellow 22–24°C, red >24°C unsanitized.
V_{gross} = \frac{L \cdot W \cdot H}{1000} \qquad V_{usable} = V_{gross} \cdot \frac{D_{fill}}{H}
Gross and usable litres — 1000 cm³ per litre, scaled by the working fill depth
Q_{rate} = V_{usable} \cdot n_{turn} \cdot \left( 1 + \tfrac{head}{100} \right) \cdot \left( 1 + \tfrac{leak}{100} \right)
Rated pump flow — turnover duty scaled by the head lift and the daily leak
Q_{delivered} = Q_{rated} \cdot \left( 1 - \frac{head}{H_{max}} \cdot 0.5 \right)
Head-corrected delivery — the rate pump derates against its max-head curve
v = \frac{Q_{L/min}}{ \pi \left(\frac{d}{2000}\right)^2 \cdot 60000 }
Line velocity — delivery flow over the pipe bore, held in the 0.5–1.5 m/s band
t_{flood} = \frac{V_{usable}}{Q_{L/min}} \quad (\text{ebb-and-flow only})
Ebb flood time — chamber litres ÷ pump delivery flow, in minutes
V_{dose} = V_{usable} \, (\text{L}) \times \frac{4 \, \text{mL}}{\text{L}} = \text{stock dose at 500 ppm}
HOCl dose — 4 mL of 500 ppm stock per litre holds ≥2 ppm active chlorine
t_{ct} = t_{base} \times 2^{\frac{20 - T}{10}} \quad (\text{temperature C×t factor})
Sterilization contact — C×t doubles the contact time for every 10°C below 20°C
n_{turn} = \frac{3.785 \cdot Q_{GPH}}{V_{usable} \, (\text{L})} \quad \text{Safety: } T > 24 \, \text{red} \; \vert \; 22 \!-\! 24 \, \text{yellow} \; \vert \; \leq 22 \, \text{green}
Turnover and the root-rot safety grade — Pythium blooms above 24°C without a sanitation line
Every litre you can carry is baked into the pump bill: a 2× turnover on a 1000 L system is not 1000 — it is a 1000+ L/h pump plus head and leak inflation, which is how undersized pumps quietly die.
Head is the silent killer of rated output. A 1200 L/h pump lifting 3 m against a 6 m max-head curve only ever delivers ~900 L/h; always size against the head-corrected number, never the box.
HOCl exists as usable hypochlorous acid only near pH ≤ 7.5; above pH ~8 the same chlorine sits as the weaker hypochlorite ion, so dosing the reservoir is an acid-then-chlorine sequence, not a solo event.
Concentration is half the disinfection story — time is the other half. Pythium is knocked out by C×t, and cool water near 15°C needs nearly twice the contact time that 20°C water does.
Reservoir temperature is a root-rot tripwire: Pythium and Phytophthora blooms switch on above 24°C, and nothing rescues a warm, unsanitized, low-oxygen reservoir.
Line velocity is a free energy audit: under 0.5 m/s nutrient settles and root mass plugs the bore; over 1.5 m/s you are burning pump watts to heat the solution, not to move it.
- Volume: 1000 cm³ = 1 L, so gross litres = L·W·H ÷ 1000 and usable = gross × working depth ÷ tank height; a mature system stands only ~80% full after root and media displacement.
- Pump sizing: turnover 1×/h DWC, 2×/h NFT and Dutch buckets, 4×/h ebb-and-flow; flow inflates 10% per metre of lift (head) and by the daily leak rate; rated output = delivered ÷ (1 − head/maxHead × 0.5).
- Ebb-and-flow: 1 ft³ = 7.48 gal and media holds ~50% of its bulk volume water (Hydroton ≈ 0.5), so the chamber sizes usable litres against the pump™s L/min, not the gross.
- Sterilization: hold ≥2 ppm active HOCl from a 500 ppm stock (4 mL per litre) at pH ≤ 7.5 where HOCl speciation peaks; disinfection contact follows C×t with the temp factor 2^((20−T)/10); UV-C needs ~1 W per 40–50 GPH of clear water.
This model combines the earlier Reservoir-volume, Pump-flow-gph, Ebb-flow-sizer, Hydroponic-reservoir-sterilization, Hypochlorous-acid-root-rot models.
Q1: How do I size a hydroponic reservoir volume? ▾
Measure length, width and height in centimetres and divide the product by 1000 to get the gross litres, since 1000 cm³ equals one litre. The usable volume is the gross scaled by your working fill depth over the tank height — plan the fill to run about 80% of capacity so root mass, media and the pump’s own footprint do not overflow. A 200 × 100 × 50 cm tank filled to 30 cm holds 300 litres gross but only 180 litres usable at that depth.
Q2: What pump flow does each hydroponic system type need? ▾
Match the turn-over duty to the system: DWC wants about 1× the reservoir per hour for oxygenation, NFT and Dutch buckets run 2× to keep the film and drip moving, and ebb-and-flow floods at roughly 4×/hour during the flood cycle. The engine then inflates that flow for the head lift (10% per metre of rise) and the daily leak rate, and returns the rated pump GPH you should buy — sized on the inflated number, not the trickle you see at the bucket.
Q3: What is hypochlorous acid dosing for root rot, and at what rate? ▾
Hypochlorous acid (HOCl) is the active, gentle chlorine species that keeps root rot and biofilms at bay without hitting plant tissue like shock chlorination. Hold at least 2 ppm of active HOCl by dosing about 4 mL of a 500 ppm stock per litre of reservoir water (roughly 2.5 mL per gallon of the concentrated product line), and keep the reservoir pH at or below 7.5 — above pH 8 the same chlorine degrades into the weaker hypochlorite ion and the dose stops protecting.
Q4: How long should sterilization contact last, and does temperature matter? ▾
Disinfection is a concentration-times-time (C×t) game: hold the active dose for the full contact window, not just until the reservoir smells of chlorine. Temperature matters because reaction kinetics are temperature-dependent — for every 10°C the water sits below 20°C, roughly double the contact time to reach the same kill. Warm reservoirs near 24°C are where Pythium blooms, so a cool, actively dosed reservoir is both the fastest and the safest line.
Q5: How is reservoir head height and line velocity calculated? ▾
Head is the vertical lift of the delivery run plus pipe and fitting friction. Your rated pump flow is the turnover ask inflated by 10% per metre of lift and by the leak rate, and the delivered flow derates at head ÷ max-head of the pump curve — half the output is gone by the time you climb half the max-head. Line velocity is delivery flow over the pipe bore; keep it between 0.5 and 1.5 m/s so nutrient does not settle and the pump is not just heating the solution.
Q6: What is the root-rot safety threshold for reservoir temperature? ▾
Pythium and Phytophthora — the classic reservoir rots — switch to aggressive log-phase growth above 24°C, and dissolved oxygen collapses in warm water at the same time, suffocating roots. The engine grades green at or below 22°C with an active sanitation line, yellow through 22–24°C, and red above 24°C or whenever the sanitation line is off, so the safety arm reads exactly what the plants are about to tell you.