DIY Proposal 04 — Irrigation & Water (hybrid: keep Autogrow, drop Growlink)
Partially replaces: vendor_teardown/07_irrigation_and_water.md — vendor charges € 4 989 for irrigation + € 9 898 for water treatment = € 14 887 combined.
Strategy
This is the one subsystem where we mostly agree with the vendor. Three vendor line items are genuinely well-chosen and not worth DIYing cheaper:
-
Autogrow IntelliDose + Peripod M4 dosing skid — real commercial hardware, 5+ year lifespan, EC/pH target matching with real peristaltic pumps. Cost €3 743 across three line items. Keep it. A DIY Atlas Scientific + ESPHome replacement would be ~€800 cheaper but give up reliability, operator interface, and replacement-part supply — all things the customer will need in year 3.
-
RO 250 L/h with software — correctly sized (3× headroom over 950 L/day facility demand) and the "plug & play with software" hints at an OEM unit with its own PLC. At €4 499 it's defensible. We might shop the same capacity from a Polish distributor for 10–15 % less, but the sizing logic is right.
-
Nanobubble oxygenator — premium, correct, hard to DIY. 25 ppm DO in 45 min is real commercial spec. €3 900 is fair, keep it.
Where we differ from vendor
Drop Autogrow Intellilink (€208)
The Intellilink is Autogrow's wireless transmission module — lets the IntelliDose talk to their cloud. Skip it. We want the IntelliDose running standalone on its local display and connected to Home Assistant via Modbus RTU or analog read-outs, not via Autogrow's cloud.
- The IntelliDose has a Modbus TCP/RTU option — check the model. If the customer's unit supports it, HA reads EC / pH / schedule state natively via the
modbusintegration. - If Modbus is not available on the customer's specific IntelliDose model, bridge via a Shelly 1PM or a Sonoff POW R3 sensing pump current → HA infers dosing runtime.
Saving: €208.
Replace Growlink Valve LINK with 4CH Pro R3 + solenoids (€299 → €0)
The vendor bills €299 per room for the Growlink Valve LINK — 5 rooms = €1 495 total just for zone-valve switching. This is 24 VAC solenoid control, which a €45 Sonoff 4CH Pro R3 in dry-contact mode drives natively. The 4CH Pro R3 is already in the automation budget for contactor switching, so the marginal cost is €0.
Saving: €1 495 (already credited to 03_automation_sonoff_ha.md).
Add what vendor missed
1. Drip lines + main pipes — the vendor marks these as "buy locally" with €0 line items. Actual cost:
| Item | Qty | Unit € | Line € |
|---|---|---|---|
| Netafim PCJ pressure-compensating drippers (2 L/h) | 240 | 0.40 | 96 |
| 6 mm spaghetti tube | 300 m | 0.25 | 75 |
| Dripper stakes | 240 | 0.20 | 48 |
| 16 mm LDPE main line | 150 m | 0.80 | 120 |
| 25 mm PEX manifold feed | 50 m | 2.50 | 125 |
| Filters, fittings, quick-connects | lot | — | 200 |
| Drip hardware | ~ 664 |
Add to DIY proposal budget. This is also the cost the customer will incur on the vendor build.
2. Fertigation-tank heater / chiller — for Malta winter / summer extremes:
| Item | Qty | Unit € | Line € |
|---|---|---|---|
| 1 kW titanium immersion heater | 1 | 80 | 80 |
| Teco 300 W aquarium chiller | 1 | 180 | 180 |
| Digital thermostat (Inkbird ITC-310T) | 1 | 40 | 40 |
| 300 |
3. Inline downstream EC/pH monitoring — verifies what actually reaches the plants matches what the IntelliDose mixes:
| Item | Qty | Unit € | Line € |
|---|---|---|---|
| Atlas Scientific EZO-EC + probe (inline) | 1 | 210 | 210 |
| Atlas Scientific EZO-pH + probe (inline) | 1 | 180 | 180 |
| Inline tee + probe housings | 2 | 40 | 80 |
| ESP32 + ESPHome for HA integration | 1 | 30 | 30 |
| 500 |
This is the second Atlas EZO kit (the first one in 03_automation_sonoff_ha.md is for emergency-only readings; this one is the inline verification loop).
DIY Irrigation + Water BOM
| Line | Qty | Unit € | Line € | vs Vendor |
|---|---|---|---|---|
| Autogrow IntelliDose | 1 | 1 840 | 1 840 | = |
| Autogrow Peripod M4 (4 peristaltic pumps) | 1 | 1 695 | 1 695 | = |
| 0 | 208 | 0 | – 208 | |
| Water filter | 1 | 132 | 132 | = |
| Water tank (main) | 3 | 194 | 581 | = |
| Nutrient tanks (A, B, pH-up, pH-down) | 4 | 29 | 115 | = |
| Tank pump | 1 | 220 | 220 | = |
| Water sensor | 1 | 199 | 199 | = |
| 0 | — | 0 | – 1 495 | |
| RO 250 L/h (shop PL distributor for savings) | 1 | 3 900 | 3 900 | – 599 |
| Nanobubble oxygenator | 1 | 3 900 | 3 900 | = |
| Permeate tank 780 L + pump + UV + levels | 1 | 1 499 | 1 499 | = |
| Drip lines + main pipes (NEW — vendor missed) | 1 set | 664 | 664 | + 664 |
| Fertigation tank heater + chiller (NEW) | 1 set | 300 | 300 | + 300 |
| Inline downstream EC/pH monitoring (NEW) | 1 set | 500 | 500 | + 500 |
| Total | ~€ 15 545 |
vs vendor €14 887 irrigation + water + the €1 495 Growlink Valve LINK allocation = €16 382.
Net DIY saving on this subsystem: ~€837, AND we fix three scope gaps the vendor left hanging:
- ✅ Drip lines + main pipes now in the bill (not "buy locally")
- ✅ Winter/summer water temperature management
- ✅ Downstream EC/pH verification loop
Confirmations needed
- IntelliDose model supports Modbus? If yes, HA reads it natively. If no, we bridge via power monitoring.
- RO brand alternative from Polish distributors — e.g., Aqua-Tech PL, Bluemen PL — can we shop the same 250 L/h capacity for €3 500–3 900 instead of €4 499?
- Which wet room layout — does the vendor's tank-heater/chiller skid fit physically, or do we need to plan space?