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Let me suggest you go to U tube and Search the Word HYDROPONIC. There are all kinds of system/equipment videos that should answer many of your questions. Yes there are system just like you are asking about. You should get some great Ideas from U Tube, I did.

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First off, I think it would be best for your friend to look around this website a bit. Using hydroponics is pretty simple, but it is a different world compared to growing with soil. Look around with google and you should find plenty of tutorials to setup and run almost any system for cheap.

What your friend is referring to is called a "NFT" or "nutrient film technique" system. You can get everything you need to setup this system at your local hardware store. Using rain gutters is one method, however I recommend using 4x4 or 5x5 PVC fence posts instead. I have also seen 6" PVC pipe used successfully. Use google to get more details.

For nutrients I would start off with either general hydroponics flora series or their maxi gro/bloom series to get a baseline. They are inexpensive, easy to use, and the PH stays very stable. Stay away from additives other than the base nutrients. Once you start getting good consistent results, then start experimenting.

Control over PH in hydroponics is critical for keeping nutrients suspended in solution and available for plants. While I highly recommend getting a nice PH probe that will measure ph/ec/temp, it's not really needed. General hydroponics sells a testing solution that will give you a fair estimate as to where your PH is.

We use a rectangular PVC channel that is called cable ducting here, pvc trunking in China, maybe something else there. We buy it at our local hardware, or electrical supply store. We get a 2 x 4" channel that comes with a removable top. We cut the holes with a hole saw bit in a hand drill. SImple.