Reservoir tank and main control tank

You may possibly be confusing Dwc with Rdwc, they are essentially the same method of growing however one setup is generally larger and slightly more complicated to setup.

Using either method of growing, it may be referred to as the 'res' or resevoir.


Dwc (first image):
Only 1 tank, bucket or resevoir (whichever you choose to call it)
It is used as both the resevoir and plant pot this requires just an airstone and air pump.

Rdwc (second image):
1 or more 'grow buckets' which are essentially the plant pots.
There is also the addition of a true resevoir tank* which adds additional volume of nutrient/water.
They are all plumbed together with flow and return pipework.
Each bucket containing a plant uses airpump/stone.
The Resevoir uses a submersible pump to equally feed all of the grow buckets with water with gravity return to the resevoir (on the principle that water always finds it's own level)


*. General rule of thumb is the volume of this resevoir should be no smaller than the volume of a grow bucket.

Snoochie Boochies!

 

I use an external reservoir tank to aerate the soup and also to slow the rate of flow into the first tank (one of two).

Since I use ultrasonic foggers in the tanks, an airstone in each tank would dissipate the fog, not good.

Ergo the external tank.

 

One tank will work as a large, external storage reservoir, but a second tank is needed to sit on top of it if you want to keep the grow vessels' levels constant automatically.

To keep water levels in the grow vessels constant, the simplest setup consists of 2 tanks.
The top tank holds fluid that eventually goes to the bottom tank thru the bottom tank's float valve.
The bottom tank is fitted with a float valve that keeps its liquid level constant, and at the same levels as the grow vessels' liquid level.
No water pump is needed if the system relies only on gravity.
That's is the system I use, and the grow area can be left untended for a few days.

 

Yes using a single large tank is fine.
I have seen other older members on here using a one tank setup with several plants.

The tank was something like 3x4 and maybe 14" tall.
I also beleive it was a DIY tank made from something like an old 1000L ibc cut down and a lid made from aluminium angle and perspex (see ref pic)

Jollyrancher1 is using a similar setup but using foggers, so the airation is done in the resevoir/control tank instead.

Each variant of this form of hydro has its uses, practicalities and drawbacks!

Pros:
If you have limited light proof grow space 1(1 plant 2x2x5 but space to fit a 'remote' tank this allows for a larger total volume of water but with easy access to add nutes, check ph perform a water change without ever opening the tent!

If you have a larger setup 8 x 5 gal buckets... you dont have to mess with every bucket 1 at a time... bam you do them all from one bucket not packed in a tent under lights.

Cons:
More involved setup.
Requires more space.
Buying "kits" are expensive and can be argued no better than an average DIYer can make with a trip to a local garden centre that has pond and fish tank supplies!

Growing multiple plants with different genetics efficiently can be problematic if nutrient requirements differ so clones are the best choice, at very least the same strain seeds.

Snoochie Boochies!

 

In layman's terms.... works like the water tank in your loft.

You turn a tap on (plant drinks)

Hot water cylinder empties (res goes down)

Tank in loft fills cylinder back up (feed tank on top)


However the system mentioned is not a recirculating system, that mearly tops up the plants as they drink.

Nothing wrong with that setup, but would be most suited to very large scale grows where the volume of fluid used in a day would be staggering.

For a small number of plants day to day topups isnt a problem.

Snoochie Boochies!