with the first grow in the thrown together box cropped, and 10 or so oz better off, the modifications began in earnest on the upgraded model.
with the experimental hydro lab about to bear fruit in 4/5 wk(fingers, toes, ball crossed), the knowlege needed to grow hydro has been hard earned so the executive decision to grow NFT style has been taken.
inside the box is 78" long and 32"wide. the hight was 5' but will be raised to 6.5'
we made a reservoir out of a frame of spars and tarpaulin finally covered with 3 layers of thick plastic (used for shrinkwrapping over pallets of bottles).
the reservoir is 75" x 30" x 12". at 2/3 capacity it holds 150 litres.
after 24hr of monitoring the res has proved to be water tight.
there is tarp streched out over the top of the res. water was poured on to it to see where is gathered and holes put in to allow drainage back into res.
two spars, one 1" thick and the other2.5" thick was paced across the length of the res to hold the NFT board.this is good quality Mdf board, water sealed and covered with plastic sheeting. cappilery matting is laid on the board and, eventually, two layers of tarp to protect the roots. 3" holes will be cut into tarp for installation of rockwool seedling/cutting blocks.
the water will be pumped up from the res into a 1/2 inch pipe laid along the long edge of the board. holes drilled into the pipe will direct the flow onto the cappilery mat, hopefully saturating it.any flow dripping off the board will drip onto the catchment tarp and then back into res.
the res has a heater and 6 x 12" air stones.
the water pump is a 1.086 l/hr job. this kind of flow will not be needed but the pump flow can be altered so all is well.
later this week the lid will go on the box and 3 x seedlings and 7 x sk1 cuttings installed.
there is still 20 seeds still yet to sprout but have all cracked and are showing 1-3mm root so should be ready soon.

this pic shows the grow box with its top off. the last box was sloped on the top. the new box will not be. the higth will also be raised to 6.5'

this pic shows the water collecting on top of the tarp covering the res. holes are put in it on the points where the water collects. the spars for the NFT board can also be seen running across

this shows the NFT board in position with its layer of matting.
anyoverflow drops off this board onto the tarp into the res!

forgot to mention, there is a 600w full spec hps ready for use and, as soon as i get starters, another four 250w son-t-pros.two will be put in the box with the 600 giving 1100w (50w/plant if 22 plants).
there is also a new carbon filter and ruck extractor (5") and 3m ducting.
a silencer will be made based on a box within a box design copied from some exhast manufacterers website. works in the experimental box so should work even better here with experience earned modifications.
humidity will be monitored due to the large amount of water in the res but hopefully, it has been made in a way so that any evaporating water in the res will not get out into the grow area (unless we need more humidity, in which case there is the option of exposing an area of the res)
please let me know if i am doin summat very wrong. i think we have everthing covered but i'v thought that before and things have still gone tits up