RDWC System Setup Guide — Step by Step for UK Growers

What is an RDWC System?

Recirculating Deep Water Culture (RDWC) is one of the most efficient hydroponic growing methods available. Unlike standard Deep Water Culture (DWC) where each bucket is independent, RDWC connects all buckets to a central reservoir — continuously circulating oxygenated, nutrient-rich water through the root zone. The result is faster growth, higher yields, and easier nutrient management compared to soil or static DWC.

MUSHROOMTEC's RDWC systems are designed and built for UK growers, with options ranging from our 4-Bucket RDWC System right up to our 12-Bucket System for serious commercial grows.

What You'll Need Before You Start

  • Your MUSHROOMTEC RDWC system (buckets, reservoir, pipework)
  • A submersible pump — our 25W or 16W Submersible RDWC Pump
  • pH and EC (Electrical Conductivity) meter
  • Hydroponic nutrients (grow, bloom, and base)
  • Net pots and growing medium (clay pebbles recommended)
  • pH Up and pH Down solutions
  • RO or tap water (let tap water sit 24hrs to off-gas chlorine)
  • PTFE Thread Seal Tape for leak-free fittings

Step 1 — Position Your System

Choose a flat, stable surface in your grow space. Ensure your reservoir sits lower than your grow buckets — gravity assists the return flow back to the reservoir. Allow at least 30cm clearance around the system for maintenance access.

For larger systems (8–12 buckets), plan your pipe routing before assembly. Our 8-Bucket ProControl System and 6-Bucket ProControl System include an integrated controller for automated pump timing and fog control, which simplifies this significantly.

Step 2 — Assemble the Pipework

  1. Wrap all threaded fittings with PTFE tape (2–3 wraps clockwise) before connecting.
  2. Connect the inlet pipes from the reservoir to each grow bucket.
  3. Connect the return pipes from each bucket back to the reservoir — these should sit higher in the bucket to maintain water level.
  4. Hand-tighten all fittings, then give a quarter turn with a spanner. Do not overtighten.
  5. Fill the system with plain water and run the pump for 30 minutes to check for leaks before adding nutrients.

Step 3 — Fill and Balance Your Nutrient Solution

  1. Fill your reservoir with water. For a 100L reservoir, start with 80L to allow for top-ups.
  2. Add nutrients according to your chosen nutrient schedule. Start at half strength for seedlings and clones.
  3. Check and adjust pH to 5.5–6.0 (the ideal range for most hydroponic crops).
  4. Check EC: seedlings 0.8–1.2 mS/cm; vegetative growth 1.2–2.0 mS/cm; flowering 1.8–2.5 mS/cm.
  5. Top up with plain pH-adjusted water daily as plants drink — never let the reservoir run below 50%.

Step 4 — Set Up Your Air and Water Circulation

Oxygen at the root zone is critical in RDWC. Your submersible pump circulates the solution, but you should also run an air stone in the reservoir for additional oxygenation. Aim for water temperature between 18–22°C — warmer water holds less dissolved oxygen and increases disease risk.

Run your pump continuously (24/7) during the grow. The ProControl systems include an integrated timer if you want to experiment with intermittent flow during lights-off periods.

Step 5 — Add Your Plants

  1. Place net pots into the bucket lids.
  2. Fill net pots with rinsed clay pebbles.
  3. Place seedlings or rooted clones into the net pots, ensuring roots can reach the water surface.
  4. For the first 48–72 hours, ensure the water level is high enough to touch the bottom of the net pot — then drop it to leave a 2–5cm air gap so roots oxygenate properly.

Step 6 — Ongoing Maintenance

  • Daily: Check water level, pH, and EC. Top up with pH-adjusted water as needed.
  • Weekly: Full reservoir change every 7–14 days to prevent salt build-up and pathogen growth.
  • Between grows: Flush the entire system with a diluted hydrogen peroxide solution (3%) to sterilise pipework and buckets.

Common RDWC Problems and Quick Fixes

  • Yellowing leaves: Usually a pH or nutrient deficiency. Check pH first — it drifts daily.
  • Root rot (brown, slimy roots): Water temperature too high, or insufficient oxygenation. Add beneficial bacteria (e.g. Hydroguard) and lower water temp.
  • Slow growth: EC too low or pH out of range. Recheck and adjust.
  • Leaks: Re-wrap fittings with PTFE tape and check all connections.

Ready to Build Your RDWC Setup?

Browse our full range of RDWC systems at MUSHROOMTEC — from the compact 4-Bucket Starter Bundle to the advanced 8-Bucket ProControl System with integrated controller, timer, and fog control. All systems ship to the UK and EU.

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