hmm.. youre math is a little wronga gallon of water weighs roughly 8.34lbs, and the entire container would be 6 inches deep but if it was filled all the way to the top, it wouldnt leave much room for good aeration, so even if it was filled up to the 6 inch point, it would not weigh anywhere near the 1400lbs of gravel, and the 8x4 by 4 inch area will only weigh roughly 600lbs...
also, i intent to have a bit of a hatch on top where i can find some free space.. atleast large enough to fit my arm in
the plants would be setting in the holes, the lip of the pot would rest on the top surface while the rest of the pot sits in.. so they could me lifted out from the top...
i could put a 1/2" piece of PVC into the bottom, and plug it with a rubber stopper like in the back of a toilet.. so all i would need to do is pull that out from the hatch to drain it into buckets below...
a question for people that have built such large deep water culture systems... about how long does it take before the solution has to be changed?
since this will be set up in a basement, im thinking of installing a float inside the resovoir, that when it drops below a certain point it will light up an
led which will be wired upstairs, maybe in my living room so that i wont miss a refill