Canna Hydro Flores SW A&B — Professional 2-Part Flowering Nutrient for Soft Water Run-to-Waste Systems
Best for: Growers running soft water, run-to-waste hydroponic systems who want proven, professional-grade flowering nutrition
Our thoughts
This is one of the best feeds available for the flowering stage in run-to-waste hydroponics, especially if you're in a soft water area. Canna's been doing this for decades and it shows — the formulation handles the mineral gaps soft water creates, so your plants get exactly what they need without you chasing deficiencies. Once it's mixed and dialled in, it just works.
Canna Hydro Flores SW A&B is a professional-grade, two-part mineral base nutrient designed specifically for run-to-waste hydroponic systems during the flowering stage. The SW (soft water) formulation is engineered for water sources low in dissolved minerals — a common situation across much of the UK. Rather than working against your water chemistry, this feed compensates for the minerals that soft water lacks, delivering consistent phosphorus, potassium, and chelated trace elements exactly when your plants need them most.
Unlike generic feeds, Canna Hydro Flores SW is built for non-recirculating systems where nutrient stability matters. You feed 1–3 times daily with 15–25% run-off, nutrients drain away, and what's left in the reservoir stays consistent. That's the opposite of recirculating setups, where minerals build up and lock out. This feed thrives on that simplicity.
How it compares
Canna Hydro Flores SW occupies the professional, proven tier of flowering nutrients.
- Water-specific formulation (SW for soft water, HW available for hard water) — competitors typically ignore regional water chemistry
- Explicitly optimised for run-to-waste systems, not a generic feed stretched across multiple applications
- Chelated trace elements for rapid, reliable uptake through the critical flowering window
- Higher price point than budget brands, but reflects decades of market trust and consistent results
- 2-part simplicity compared to 3-part systems, reducing mixing complexity without compromising nutrient control
You're paying for specialist formulation and brand heritage, not marketing hype.
Usage guidance
Dosage and mixing
Use 2–4ml/litre of both Part A and Part B, depending on plant vigour. Start at 2ml/litre for lighter feeders, move to 4ml/litre for heavy-feeding plants. This creates an EC of 17–23, the optimal range for flowering. Fill your reservoir with water first, add Part A, mix thoroughly, then add Part B. Never mix the concentrates together undiluted — insoluble compounds form that plants can't absorb.
Application frequency
Feed 1–3 times daily. Run-to-waste systems are designed for frequent, lighter feeds with consistent 15–25% run-off. This keeps the reservoir fresh and prevents nutrient build-up.
pH and EC monitoring
Maintain pH between 5.2–6.2. Use an EC/CF meter (a Bluelab Truncheon is industry standard) to keep nutrient strength in the 17–23 range. Flowering responds better to stability than aggression — small, consistent feeds beat sporadic heavy ones.
Reservoir management
Renew your nutrient solution every 7 days. This prevents nutrient imbalance and keeps the feed performing consistently. Measure concentrate with a syringe or beaker for accuracy — eyeballing it will cost you consistency.
Plant-specific adjustment
The dosage rates above suit vigorously growing, healthy plants. Slower-growing plants or those recovering from stress need lower dosage. Watch your plants, not just the chart.
Technical specifications
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System type: Run-to-waste hydroponic (not suitable for recirculating systems)
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Growing medium compatibility: Rockwool, clay pebbles, and other soilless mediums
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Growth stage: Flowering phase onwards
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Format: 2-part concentrate (Part A and Part B)
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Dosage: 2–4ml/litre of each part
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EC range: 17–23 (CF equivalent)
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pH range: 5.2–6.2
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Nutrient composition: Mineral-based with high-quality macro and micro nutrients, including chelated trace elements for rapid uptake
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Water type: Soft water formulation (HW variant available for hard water areas)
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Application frequency: 1–3 feeds per day
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Reservoir renewal: Every 7 days
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Available sizes: 1 litre, 5 litre, and 10 litre bottles (Part A and Part B sold separately)
Who this is for
- Experienced run-to-waste hydro growers who understand system management and want proven performance
- Growers in soft water areas (much of the UK qualifies) who've struggled with generic feeds not compensating for mineral gaps
- Anyone running clay pebbles or rockwool who wants a feed built for their specific medium
- Intermediate growers ready to move beyond entry-level nutrients to professional-grade formulations
- Operators running multiple systems where consistency and reliability directly impact results
Not suited to beginners without hydro experience, or recirculating systems where nutrient reuse is the goal.
Our take
Canna Hydro Flores SW is one of the best feeds available for flowering in soft water run-to-waste systems. It's built by a brand with decades of credibility, optimised for your water chemistry and your system type, and formulated to support steady, reliable flower development without drama.
If you're running soft water hydroponics and want a proven bloom feed that actually accounts for your regional water chemistry, this is worth picking up while stock lasts. Does exactly what it should, day in, day out.
