A little intro, first sorry for lurking, I like to check our a place before I register. Second I am a aquaponics guy (Been using aquaponics off and on for about 6 years), but earthships in principal fascinate me. But I heard that some of the older ones are beginning to have their greywaters crash.
So I was in the process of mocking up one of Reynolds grow beds to test with, when I got interrupted (I'm sure that never happens to anyone... J/K). So I kinda let the project sit (See attached pic). So here is what you are seeing. The little pipe at the bottom constantly pumps water into the "Growbed". The big pipe has gravel all the way around it on the bottom (Just like Reynold's... Well the gravel is a little smaller given what I am working with). The far end has a stand pipe so I can maintain the water level. What I am seeing is this... There is no surface flow. None. Which means the water is taking the easiest path, as we would expect.
So in aquaponics we have two main types of bacteria, aerobic and anaerobic. Short version, aerobic is what we try to cultivate to break down nutrients to be plant usable. Anaerobic takes the same nutrients and locks them up... There are those who think there should be some anaerobic areas, especially in the filter. I'm not one of them. The thing the aerobic bacteria need to survive is oxygen. If the only time you are adding oxygen is when you wash your hands or take a shower the aerobic bacteria will eventually die. It probably wouldn't be noticeable for a while they would have to use up all the oxygen in the water. But I think this is why they see the big difference with the recirculating pumps. As the water is pumped back it adds air when it strikes the other water. Which is good. But I think it could be added on just a bit further. I think if you added a simple venturi to the recirculation line and plumbed it to below water level the added mixture of air would make the beds thrive. This if done right, would also allow easy nutrient adding to the growbeds.... a 5 gallon bucket of compost tea, and put the intake from the venturi in it. Once the hose runs out of liquid to suck up it will pull air.
I don't have time to crash a grow bed obviously, but I will be experimenting with this idea more. What do you folks think?
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