Yesterday we started washing gravel and putting it straight into the completed growbeds. We have 12 tons of gravel on site and this MAY be enough for half of the Growbeds. Everything in this project is on such a large scale. When I build a drain, I have to build another 71 before I am finished. Each drain takes 3 clamps, so there are 216 clamps to be fitted and tightened correctly.
The mathematics that goes into the flood and drain cycle is also pretty complicated. One has to calculate the total water in the system, 3 x 7800L tanks plus a 5000L sump = 28400L of water. The water to flood a half or a quarter of the grow beds, taking into account the space the gravel occupies is also a factor. How long it will take to flood a section, how long it will take to drain the water from one growbed through 3 x 10mm drain holes etc. etc.
Then the timers get set and the test commence. Pump too long and you drain your sump and burn out a pump. Pump too short and the growbeds don’t fill properly and the plants die. The list goes on and on.
Here is an image of the first gravel going in, some filled growbeds after day #1 and a close up of the gravel. It’s about 10-13mm.
I am feeling extremely ill from inhaling so much PVC dust as well as PVC fumes from the plastic welding. My chest is tight and my throat is very sore. This stuff is highly toxic and I have got to try to be more careful next week.
I have increased the size of the outer drain pipe to 110mm on the advise of one of my Backyard Aquaponic mates in Oz and it really seems to be better for maintenance. At least I can sort of get my big paw in now.
Enough for now.