Growrilla Hydroponic system 2.0 RDWC 4

Four pots in two rows, on 80 by 105 centimetres. The size that fills a 120 by 120 tent the way it was meant to be filled.

The Growrilla Hydroponic System 2.0 RDWC 4 is the most popular size in the range, and that is no accident: a 120 by 120 tent is the standard most growers settle on, and four pots at 50 centimetre centres fill it exactly. You keep room to walk around it, and the controller pot sits at the end where you can reach it.

Compared with the two-pot system the air pump steps up to a V20 at 20 L/min. That is necessary. Four root masses need more oxygen than two, and aeration is the one component in hydroponics you should never economise on.

One 75-litre reservoir for four plants

Everything you do here happens at the controller pot. That is where the water pump sits, where the tap is, and where you measure and correct. The solution circulates continuously, so whatever you add reaches all four pots at the same concentration within minutes.

This is the real advantage of the system, and the point new hydro growers most often underestimate. Four separate buckets means measuring four times, correcting four times, and four plants drifting apart from each other. Here it is one action.

EC and pH: what to measure and when to act

In hydroponics the nutrient solution is everything the plant has. There is no substrate holding nutrients and releasing them slowly, and no buffer to absorb a mistake. What is in the water is what the plant gets. That makes two numbers matter more than anything else.

EC tells you how much nutrient is in the water. It almost always rises during a grow, which surprises people. The reason is simple: a plant takes up more water than nutrient. Proportionally more water leaves the reservoir than salt, so what remains gets more concentrated. Top up with plain water and you dilute back down. Top up with full-strength nutrient and you stack it up: the classic way to burn your own plants while believing you are doing everything right.

pH determines whether the plant can reach those nutrients at all. Every element has an acidity range at which it is available. Sit outside it and the element is simply present in the water with the plant unable to use it, so you see a deficiency while the reservoir is full. That is why "give more nutrient" is so often exactly the wrong response to a deficiency symptom.

Measure daily, at the same time of day. Not because something goes wrong daily, but because it is the movement of those numbers that tells you what your plants are doing. An EC climbing three days running means something different from an EC that wobbles.

Technical Specifications:

• System type: RDWC recirculating hydroponic system
• Growing pots: 4 x 19 litre (Ø 30 x h 33 cm)
• System rows: 2
• System water volume: 75 litre
• Plant spacing: 50 cm
• System footprint: 80 x 105 cm
• Recommended growing area: 120 x 120 cm
• System power: 27 watt
• Air pump: Hailea V20 (20 L/min, 1200 L/h)
• Water pump: Hailea HX2500 (650 L/h)

Frequently asked questions

Does this fit a 120 by 120 tent?
Yes, that is what it was designed around. The footprint is 80 by 105 centimetres, so you keep working room on every side. If you need it narrower, slide the pots closer along the pipework; plant spacing is not fixed.

What EC should I run?
That depends on your nutrient line and the stage of the plant, so follow your manufacturer's schedule. More important than the exact figure is measuring daily and knowing which way it is moving.

How often will I need to top up?
In full flower four plants will take five to ten litres a day. With 75 litres in the system that means topping up every few days. Do it with water you have set the EC on, not with plain tap water.

Can I use this with coco or soil?
No. The pots are made for net pots with clay pebbles and roots hanging in solution. Substrate in a DWC pot holds water, blocks the pipework and defeats the whole principle.

How much electricity does it use?
27 watt for both pumps together, running continuously: roughly 20 kilowatt-hours a month. Next to your lighting it disappears.