Newb for Hydro Ron's 11 plant system

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I have almost finished building this setup, but I had a few questions that I could not find. How is the plant placed in the soda bottles? Do you just put grow rocks or something straight in the bottle or do you need some kind of cup? And if you do first put it in the cup, how do you place it in the 2 liter bottle? Second I was wondering how much water you fill the 10 gallon reservoir. Thank you so much