Nice grow room setup you built, too bad for the loss, you fail to mention at what ph you're running as well as what ppm's, you're right abt having the flow hit directly at the plant, not a good idea, the GH flora series you're using to me is an excelant choice, but the dosage they suggest is way too high, once mixed I measured and it read over 1800 ppm's, to me that would burn your plants, you should be around 800 or slightly more, I've been using it for yrs with no problems, not sure abt reservoir temps, I've never payed attention to it, never used cal mag and never had the need, I grow in rockwool cubes as well as hydroton, never could understand why people seem to think it's needed, just my opinion, never used any additives, as far as I'm concern as long as you feed your plants you don't need them, to me they're a waste of money, I'm wondering if the flow of nutes was sufficient to fill the pots allowing for all the hydroton to get moist, didn't mean to make this a long answer but couldn't resist...best of luck next time.
