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Category 02 // Hydrodynamics & Mass Balance
Water Chemistry & Fluid Dynamics Suite
Deterministic aqueous solution modeling, Henry’s Law dissolved gas equilibrium, titration curves, and mineral stoichiometry. Calibrated for sterile aeroponic reservoirs and automated multi-channel fertigation manifolds.
±0.005 mS/cm ion accuracy
Henderson–Hasselbalch buffers
Henry’s Law NIST 25°C
JSON / MODBUS export
Aqueous Guarantees
ENGINE PROFILE
ION ACCURACY
±0.005 mS/cm
BUFFER MODEL
Henderson–Hasselbalch
HENRY EQUILIBRIUM
NIST 25°C Ref
TELEMETRY EXPORT
JSON / MODBUS
RUNTIME
CLIENT-SIDE
EXPORT
JSON/CSV/REST
Standard Engines in this Category
Water Chemistry & Fluid Dynamics Suite — Engine Catalog
8 of 32 deterministic tools
ENG-10790
LIVE ENGINE
EC / PPM / CF Converter Hub
One hub for the grow-room numbers games: convert EC (mS/cm), PPM on the 500 / 640 / 700 scales and CF in…
EC₂ⁱ = EC_T / [1 + 0.0191(T − 25)] · PPM₀₅ = EC₂ⁱ × 500 · PPM₂ = EC₂ⁱ × 700 100% CLIENT-SIDE DETERMINISTIC Launch Engine
ENG-10791
LIVE ENGINE
Reservoir Change Timer — EC Drift & Flush Schedule Blueprint
A hydroponic flush timer that reads your log like a journal: EC current = 1.8 + drift × days + salt term,…
Turnover = V_res / V_added_per_day · Flush when TDS_drift > 25% 100% CLIENT-SIDE DETERMINISTIC Launch Engine
ENG-10792
LIVE ENGINE
Dissolved Oxygen Calculator — Saturation & Aeration Blueprint
A dissolved oxygen calculator that starts from the saturation ceiling your water can actually hold — the Benson & Krause 1984 temperature…
DO_sat = exp(−139.344 + 1.5757×10⁰₁₄/T_K − 6.6423×10⁰₂₂/T_K²) × P_atm / 101.325 100% CLIENT-SIDE DETERMINISTIC Launch Engine
ENG-10793
LIVE ENGINE
Dosing Pump Calibrator — Peristaltic Flow & Timer Blueprint
Dose the reservoir without guessing. Enter the reservoir volume, the EC target and the pump's rated flow — the engine derates that…
t_on(s) = (Target_mL × 60) / (Q_rated × η_viscosity) 100% CLIENT-SIDE DETERMINISTIC Launch Engine
ENG-10794
LIVE ENGINE
HOCl Solution Maker — Hypochlorous Acid & Bleach Dilution Blueprint
Make an HOCl solution by volume instead of guessing: bleach mL = target ppm × volume ÷ (bleach % × 10 ×…
V_bleach(mL) = (PPM_target × V_L) / Stock_ppm · [HOCl] = FAC / (1 + 10^(pH − 7.53)) 100% CLIENT-SIDE DETERMINISTIC Launch Engine
ENG-10795
LIVE ENGINE
pH & Alkalinity Architect — Buffer Blueprint
pH buffer architect. Runs the carbonate equilibrium and alkalinity titration for your reservoir — then doses the exact mL of acid or…
pH = pKa₁ + log⁰₁([HCO₂⁻] / [H₂CO₃]) · mL_acid = ΔAlk × V / N 100% CLIENT-SIDE DETERMINISTIC Launch Engine
ENG-10796
LIVE ENGINE
Reservoir Volume & Dosing Engine — Volume, Flow & Sterilization Blueprint
The Pro-level sizing and sanitation blueprint for a hydroponic reservoir. Enter tank dimensions, working depth and head lift and the engine returns…
V_eff = (L × W × H_work) × 0.92 · TDH = H_stat + h_f(Darcy) 100% CLIENT-SIDE DETERMINISTIC Launch Engine
ENG-10797
LIVE ENGINE
Water Quality Analyzer — Hardness, RO & Treatment Blueprint
The feed-water screener for a hydroponic reservoir. Pick a water source type, drop in the pH, EC and hardness in ppm CaCO3,…
SAR = [Na₂] / √(0.5([Ca²₂] + [Mg²₂])) · RO_perm = CF × (1 − R) 100% CLIENT-SIDE DETERMINISTIC Launch Engine
Agronomic Methodology
Why Water Chemistry Dynamics Dictate Root Zone Absorption
Dissolved salts do not sit inertly in an aeroponic reservoir — every ion pair exists in a thermodynamic equilibrium mediated by temperature, bicarbonate alkalinity, and redox state. Ionic bioavailability is a function of dissociation, not of the mass poured into the tank.
Each engine in this suite normalizes readings to the 25°C standard state, corrects carbonate buffering against Henderson–Hasselbalch equilibria, and models Henry’s Law gas ceilings so dosing decisions are made on true ionic concentration — never on a raw probe number.
Standard Operating Procedure
Four-Stage Chaining Protocol
Deterministic capture → solve → steer → record chain for this domain.
STAGE 01
Capture
Reservoir conductivity and temperature are read together, because a raw EC value is meaningless until it is anchored to a known temperature.
✓ Two-channel probe
STAGE 02
Normalize
Apply the 1.91 % per °C mobility correction to bring the reading onto the 25 °C standard before any scale conversion happens.
✓ ±0.02 mS/cm
STAGE 03
Convert
Project the normalized value onto the 500 and 700 ppm conventions and derive osmotic pressure in bar for the root zone.
✓ 2 scales + bar
STAGE 04
Record
Store EC at 25 °C, both ppm scales and osmotic pressure so drift can be separated from genuine concentration changes.
✓ JSON / CSV export
Category Literature & Peer-Reviewed Reading
View all 171 posts
Research Library
Nutrient Solutions
5 MIN READ
Runoff EC Drift: Reading Your Medium’s Health
Runoff EC drift is the medium's audit trail. Field capacity is locked per medium — coco 75%, rockwool…
Read Guide
Nutrient Solutions
6 MIN READ
Reservoir Change Checklist: Add-Back vs Full Flush
The add-back vs flush decision is math, not routine. The reservoir model grows EC off a fresh 1.8…
Read Guide
Nutrient Solutions
5 MIN READ
Fallout Prevention: Mixing Nutrients In the Right Order
Nutrient mixing order is what keeps salts in solution instead of falling out as precipitate in the tank:…
Read Guide
Physical Constants Benchmark
Domain Constants & Tolerances
Authoritative constants, units, source basis, and measured tolerances for this domain's solver.
| Constant | Symbol | Value | Unit | Source | Tolerance | Status |
|---|---|---|---|---|---|---|
| EC temperature coefficient | θ | 1.91 | % / °C | Ionic mobility | ±0.05 | |
| Osmotic pressure per mS/cm | π | 0.36 | bar | van 't Hoff | ±0.02 | |
| NaCl scale factor | k500 | 500 | ppm / EC | Conductivity convention | exact | |
| KCl scale factor | k700 | 700 | ppm / EC | Conductivity convention | exact | |
| Bicarbonate pKa at 25 °C | pKa1 | 6.35 | – | Henderson–Hasselbalch | ±0.02 | is optimal |
COMPUTATIONAL FAQ
Frequently Asked Water Chemistry Questions
Deterministic answers from the domain solver, verified against the published tolerances.
01 Why must EC be normalized to 25 °C before comparing readings? ▾
Ionic mobility rises with temperature at roughly 1.91 % per degree Celsius, so a probe reading at 18 °C reports about 13 % lower than the same solution at 25 °C. Normalizing keeps reservoir history comparable across seasons and chambers.
02 How do the 500 and 700 ppm scales differ from true EC? ▾
Both are conversions rather than measurements: the 500 scale multiplies EC by 500 using a NaCl calibration and the 700 scale multiplies by 700 using KCl. Neither describes the actual salt composition, so EC in mS/cm remains the only directly comparable unit.
03 Why does pH drift upward after mixing nutrients? ▾
Bicarbonate alkalinity consumes the acidity that would otherwise hold pH down, and the carbon dioxide that forms is slowly lost to the air. The result is a steady upward drift until that alkalinity is neutralized.
04 How much acid does alkalinity removal require? ▾
Acid volume scales with the alkalinity to remove, the reservoir volume and the acid normality: (Alk_initial − Alk_target) × volume × normality. Measure alkalinity in ppm as CaCO3 instead of guessing the dose from pH.
05 What is the relationship between EC and osmotic pressure? ▾
Osmotic pressure is approximately 0.36 bar per mS/cm at 25 °C for a typical nutrient solution. That pressure is what the root must overcome to draw water in, which is why high EC eventually costs yield even when every element is present.