Hi, I've been fascinated with this especially for tomatoes! I'm wondering a) how much you have to top up, and b) how long a bottle of nutrient solution lasts. I think someone on a forum said a 15 quid bottle should last you a season, in which case I'd be happy. As far as I could see, you start your seeds on tiny bits of soaked rockwool in a propagator, then you stick them in bigger bits til you reach the rockwool block size. You then plant them in your nft system resting on top of a sloping capillary mat covered piece of plastic. The pump shifts the stuff to the top of the slope and gravity does the rest.
My questions, how often do you test your medium? How many plants can you get into say a 3 ft (1 mtr) pod? Also, it seems the support is the main problem.. any advice, or is wire from above the way to go? And the main one, on a hot day in the green house, even with shade, how much you top up each week?
Like I said, I've been interested, but until you know someone to show you, it's hard to justify the investment.