Plantzilla is what Melissa has taken to calling the aquaponics system I have been setting up - a seemingly appropriate name with the rapid plant growth we've been seeing. In my last post I left off after having just completed the fish tank and grow bed and just before getting the plumbing working. Fast forward a few weeks and the plumbing is all working fine, we've been cycling the water, planted plants and now have 15 little tetras and danios swimming around in the fish tank.
The plumbing is fairly standard from what I've seen of other aquaponic setups. A pump in the fish tank pumps water up into the grow bed through some black vinyl tubing. There it floods the grow bed until it reaches up just below (about 2") the surface of the hydroton, filling the grow bed before it starts draining out of a PVC stand pipe that exits out of the grow bed through a bulkhead.
The stand pipe is itself surrounded by a larger PVC pipe fitted with an end cap and little holes cut into the bottom, allowing the water to actually get up to the stand pipe. This second pipe is very important - by placing it there we are constructing a bell siphon; once the water reaches the standpipe and pushes some air out, the siphon will kick on and drain the entire grow bed in a timespan of roughly 30 seconds! Once the water is drained, air will get back inside the piping and kill the siphon, allowing the grow bed to fill back up. This flood/drain cycle provides the plants with all the water and nutrients they need without, you know, drowning them...
Some might also take interest in the larger bit surrounding the bell siphon - my media guard meant to keep the hydroton and roots from getting into the pipework, as well as allowing me to easily remove the bell siphon piping if need be. I spent a while deciding what to use here - it's apparently not so easy to find large enough (~4") PVC piping that is rated for potable water use, and I see a lot of people online using DWV or ABS PVC. I wanted to be a little more certain that what I was getting was actually ok for potable usage so I went ahead and actually purchased a large HDPE bottle off Amazon and sliced a hole in the bottom to make my media guard.
Before adding the fish to the system I went with a fishless cycle. This basically means just introducing some ammonia source into the system, letting the bacteria in the grow bed establish itself so it can process it into nitirites and then nitrates. To do this I ended up purchasing some bottled guano (seriously stinky) and added some to the water. It turns out that little bit of it goes a *long* way; I added two capfuls of it at first and ended up with ammonia levels that were way beyond the limits of my test kit. I ended up changing most of the water out before establishing a stable system.
In the meantime I saw no reason to wait to start the plants growing, so I went ahead and purchased a few and got them transplanted. So far I have planted a couple cherry tomato plants, zucchini, basil, bell pepper, jalapeno and a sweet pepper. I'm still planning on planting habanero (can you tell I like spicy food?), strawberry and possibly some sort of leafy green.
And finally - the fish. Once the water levels started looking good we headed out to an aquatics store - Neptune Aquatics - to get some fish and other supplies. We had a notion that we would just put a few goldfish in there, but I left this bit more up to Melissa's discretion. We ended up going with a larger number of smaller schooling fish. So far so good; they swim around, they eat and then they poop - I can't ask for much more than that. The plants are certainly liking it, particularly the tomato, which I have now got growing up through a net coming down from above the grow bed.
Oh, and since our cats are absolutely fascinated by running water, obligatory cat photos (Melissa must have like 100 of these...):
They don't seem to realize there are fish in the tank. Yet... but I've built a plywood and plexiglass lid to keep them out.
That's it for now, I probably won't update about this again until we actually have some produce from the system.