RDWC System 6 x 27L Buckets – Recirculating Deep Water Culture for Indoor Growing

RDWC System 6 x 27L: active recirculation and root-zone oxygenation for six plants indoors

The 6 x 27L RDWC System is a recirculating hydroponic setup built for indoor growers working in grow tents or greenhouses. It brings together six 27-litre buckets in food-grade, light-proof PP/PE plastic, linked into a closed loop by 25 mm fittings. Unlike a standard DWC where every bucket behaves as its own isolated reservoir, continuous recirculation equalises pH, EC and temperature across all six sites: what you measure in the reservoir is genuinely what your roots are drinking. With 162 litres in motion, the thermal and chemical inertia of the loop absorbs swings and limits drift between checks — a decisive advantage on long runs and large plants.

Full technical specifications

Key benefits of the system

Setting up and running the system

Level the circuit before anything else

Levelling is the single most decisive step in an RDWC install. Stand the six buckets on a genuinely flat surface — a concrete floor, a rigid pallet or a spill tray — and check with a straight edge and a spirit level that every base sits at the same height. A single centimetre of difference between two buckets creates a water-level imbalance that drowns roots on one side and leaves them dry on the other. Then connect the buckets with the 25 mm fittings, hand-tighten the seals and run a 24-hour test with plain water before planting anything: that is the only reliable way to find a micro-leak before it happens with nutrient solution and plants in place.

Choosing the pump and setting the flow

The submersible pump is not supplied, so you size it against the real head height of your installation and your target flow. Aim for enough circulation to turn the loop volume over several times an hour without whipping up turbulence inside the grow buckets. An oversized pump agitates the root zone needlessly and dumps its own heat into the water; an undersized pump lets the loop stratify and cancels out the whole point of recirculating. Sit the pump in the reservoir, add supplementary aeration if you grow through warm weather, and run it continuously, day and night — an RDWC is not cycled like an ebb and flow table.

Water temperature and daily monitoring

Nutrient temperature is the critical variable in any deep water system: warmer water holds less dissolved oxygen and lets root pathogens take hold. Keep it cool and stable by shielding the buckets from lamp heat and adding a chiller if your room climbs in summer. Check pH and EC directly in the reservoir every day at first, then every other day once you know the uptake rhythm. Top up with plain water as the level drops, and carry out a full solution change every one to two weeks depending on stage — vegetative or flowering — to stop salts accumulating and nutrient ratios drifting.

Frequently asked questions about the 6 x 27L RDWC System