Growbox is now fully funclional - lights and hydroponic system are now working and automatically controlled.
As i mentioned before, hydroponic system construction was reviewed, as old idea of leak-proof system was too complex to maintain compared to systems with reservoir separated from growing media box. It's much easier to have independent, mobile nutrient solution reservoir. So i've bought (from Auchan this time) two non-translucent 30litre plastic boxes which fit my cabinet even better and two 16litre buckets. Also (from OBI) 4m of plastic hose 12/2mm, two water pumps for indoor fountains (6W, 300 l/h), hose connections, hose clamps and vermiculite, though the latter finally has not become main growing medium.
Lamp height was planned for higher box (35cm), though new boxes are 15cm high. First approach was moving the whole shelf up, though after completing this i realised that it's much better to have boxes above the shelf, with their bottom sides accessible for hose connections, so i've put shelf back down and made a wood frame to put boxes on it.
Those boxes have wheels attached to small spinnning platforms, and there are tube-shaped mounts at the bottom of box. Those tubes are too large for 12/2mm hose, though the tube-shaped part (yellow one) of the wheeled platform fits the hose just perfectly. Though it's not very tight connection and would leak withough a clamp, if pressure is applied to liquid inside. That's fine for overflow tube. For pump hose there's more reliable connection made out of bigger factory-made hoze connection. It's larger than the hose, but it makes connection tight enough to handle the pressure, even without a clamp.
Connections are soldered in with soldering iron. Black plastic is different ot blue one, though adhesion is quite good anyway.
There are two yellow connections: outside and inside, these ones are for overflow tube. Inside connection has a short piece of hose attached to it, that hose has holes at sides of the upper tip, just at the level i don't want nutrient solution to reach. This tip is wrapped in gauze, just to avoid hard particles from being sucked into the hose. Overflow is unlikely to happen too often, as pump is timer controlled and it will be turned on just for enough time (3 min) to fill the box up to the desired level. Black connection is for pump hose. This hose will do most of the work. Water comes up to the box when pump is working and goes back to reservoir when pump goes off.
Testing with water is successful, though at first time water level was too low, so i had to raise the buckets a bit - just the same distance water level lacks in the box. Pumps are small and weak, they can raise the water 80cm up and no further, but that's just fine for my system, even adds one more level of leak protection. It turned to be even better to have buckets raised a bit, it's easier to move them out this way.
Boxes are filled with growing medium - small pellets of expanded clay. Buckets are filled with nutritient solution (mineral fertilizer + water). 2nd lamp is in place and chile plants are moved in the system. System is launched! It has 16 hour light day and pumps work 4 times a day for 3 minutes.