How do barrel reservoirs work?

I've seen hydro setups where there's a 55 gal barrel reservoir next to the system. The barrel is set at the same level as the plants.

So, how does this work? Do they use two water pumps (one to send water to the sprayers and one to send water from a bottom "catch" reservoir back the barrel), or are the sprayers gravity fed or something?

I'd like to set up an external reservoir. It would definately make things more convenient. But, if it entails syncing up pumps and there's higher risk involved for something to go wrong then I'll probably just avoid it.

Sounds like the "ebb & grow" system they sell at hyrdroponic shops to me.
The barrel is connected to a controler bucket.
The controler bucket has 2 water pumps and 2 float valves. It has a big timer on it to control the flood and drain settings.

http://www.4hydroponics.com/hydroponics/Mnl/ebbFlo.pdf


This system seems to work well from what i read though I would never try to build one myself since the chance of flooding your area with 55 gallons of nutrients is very possible. Also keep in mind you have to drain and replace 55 gallons every week most likely with a 5 gallon bucket or a really long hose. The 55 gallons would be great for keeping ph stable though.

There is another similar system called the living system or something that has gotten tons of bad reviews because it leaks and doesnt circulate well.

hope that helps

Here's the system I use which is very similar to the one Joesmama posted. It works like a charm. I utilize 2 - 55 gal barrels: one with nutes and one with a reserve of RO water to switch over to on flush day (every 2 weeks).

http://www.hydroponics.net/items/details/multiflow.asp


Good Luck Amigo

Thanks everyone, I got it now. I wasn't really looking to use a 55 gallon barrel. More like a 20 gallon sterilite that could be placed outside my box, giving me a little more room inside.

I'll stick with what I've got. Here's my setup right now...


My Veg Box...




My grow box reservoir (This was taken a couple weeks ago so the plants are smaller. The top pic is more recent)...



My Bloom Box...


Bloom box reservoir...


Bloom box upskirt (looking up 5' - 6' plants in a box with a 9' ceiling)...