So, last weekend I had a helping hand from my FIL to weld two steel legs onto the corners that had wooden ones and we added extra support with timber beams wherever I could get them without making too much of a complicated structure.
The pump arrived yesterday (Wednesday) so today was the day to set that up. The box looked quite small when I picked it up from the post office. Inside was a smaller box still and when I opened that I found the pump tucked in with foam, making the pump smaller still!
And yet, it works!
There is enough pressure in the pump to get water entering the grow beds. I did a test run and found that the beds emptied much to quick in comparison to the speed that water was entering and so they were not filling and the 90mm drainage pipe was overflowing. I had drilled two holes in the bottom of the standpipes for each bed and I filled in one of these to assist with a slower drainage time. Then I drilled more holes into the polypipe that transports the water to the grow beds. I’m waiting for the sealer to dry now before I give it another test.
I have also piped together the two fish tanks with a tap incorporated into it so I can isolate the tanks if need be. The primary job of this piping is to equalise the water levels between the two tanks whilst water is being pumped out of the front tank and then to equalise again once water starts to flow back into the tank. In this way I can also keep two varieties of fish ie. goldfish in one and silver perch in another. Plus with the number and volume of grow beds I can easily accommodate two tanks. I designed the system so that, as suggested, there is more grow bed volume than tank water volume in order to allow the water to be properly filtered by the plants and microbes. I also had set it up so that each grow bed can have different plants at different stages and still support the system, even if at 50 % capacity. The other advantage of having numerous beds is that I can experiment with different techniques for each and compare the results.
The finished design is even simpler than my drawings and workings. Wherever possible I have made the pipes the shortest length possible to allow easy flowing of water both to the grow beds (reducing friction for the pumped water) and from the beds in the drainage pipes. I noticed that the water drained much better if allowed to fall into the fish tank rather than having a longer pipe submersed in the water which created a lot more friction and resistance.
The next thing is to move the goldfish and let the pump run for a bit to wash out the remaining gravel dust. Then I’ll let the water be still to settle the dust and then vacuum it out from the bottom of the tank. I am thinking of using Redfin Perch initially in the front tank and goldfish and marron in the second.