R-DWC is a special type of DWC setup. It is where several DWC bubblers are connected together and a pump circulates the nutrient solution around them. This increases the oxygenation still further, and keeps the nutrient solution well mixed and even between the pots. R-DWC is reported to be advancement over and above the excellent results that can be had with standard DWC. High oxygenation makes it difficult for root diseases to survive, however, we would still recommend using Silver Bullet Roots just to make sure.
Air Flow Rate
For DWC and R-DWC to work properly, each bucket needs to be supplied with at least 1 Litre of air for every 4 litres of water, per minute.
That means that for a 10 litre DWC bucket, it will need to be supplied with 2.5 litres of air every minute. That's the same as 150 litres per hour.
Air Pumps, Air lines, Airstones and Check Valves
Supplying the DWC bucket with air will require the use of:
- An air pump
- Air line to connect the pump to the bucket
- A check valve (one way valve) to prevent water ever siphoning from the bucket back into the pump
- An airstone to create a plume of fine bubbles
In the example above, you might think that a 150 Litre / Hour air pump would be good for the job of running one 10 litre DWC bucket..
Unfortunately, the check valve, the airstone, and each metre of air line resists the flow of air. which means that by the time the air comes out of airstone, the flow rate is likely not to be 150 Litres per Hour. This will be particularly true when using cheap air pumps and where there are long lengths of air line.
To ensure there is enough air being supplied to the DWC bucket we would recommend doing the following:
- Getting a good quality air pump which can supply a little more air than needed than in the calculation above
- Keep the air line as short as possible
- Use a good quality airstone
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