(FYI: This post is mostly a recap from what you’ll find over on the Garden Wiki Forum. It’s popular enough that a blog entry seemed logical!)
The major point of frustration I’ve had setting up my aquaponics system is in figuring out how to plumb the containers. I had no idea what I needed, and I’ve since learned about terms like “bulkhead fitting” which roughly means a water tight connection into whatever water chamber you may be working with.
My first goal was to learn how to put a bulkhead fitting in place on a test container, for which I chose the plastic crate you can see here. Quickly learning that bulkhead fittings are not something you can usually find at a hardware store, and not wanting to bother plumbers or pay a lot from online sources for specialty parts I decided that whatever the case my system was going to be composed of a do it yourself set of parts I would be able to find cheaply and from a normal hardware store. What’s the point of tinkering if you have to depend on lots of external sources, right?
What I ultimately found was advice online about how to build an improvised PVC based bulkhead fitting for aquaponics. The current wisdom (which I’ll improve greatly upon if you keep reading) seems to be that to build such a thing you have to avoid normal PVC and head into the electrical PVC section of your local hardware store and you end up using electrical male and female PVC adapters because they fit tighter together and with glue and some gaskets/orings you can build your own bulkhead fitting for just a few bucks. This didn’t work for me because I was unable to find gaskets/orings.
Instead I’ve found some absurdly easy to come by things at my local Lowes and used them on the crate you see in the image above and on everything else in my system now. The items are as follows:
A 1/2 inch FEMALE electrical (gray) PVC threaded adapter.
A 1/2 inch MALE normal (white) PVC threaded adapter.
A rubber washer made for a garden hose.
So why do these things work for my aquaponics setup?
Because the male and female adapters screw into each other well. The choice of using a normal PVC male adapter is because they seem to be made with longer stems, which didn’t matter on the thin side of the test crate shown here but when I eventually went and tried this on a 55 gallon plastic barrel I needed that extra stem length to go all the way through. The washer, which I found 6 packs of for $1 but could have simply stolen out of a garden hose from my very own yard just happens to fit (very) snugly over the stem of the male PVC fitting, 1/2 sized only, thus my choice of 1/2 inch PVC. So when you look at the picture above you simply see that I ram a hose washer onto a male 1/2 inch PVC adapter, slip the remaining stem through the hole in the container, and then the female (no washer on the back side, just pvc) electrical pvc adapter gets screwed in.
Even better, I’ve experienced little to no leakage on various containers. The sheer pressure of smashing that washer between the male bit and the outside of containers seems to be pretty water tight. No glue, less hassle and I find I can take them back off in a heartbeat to change things up, which is great for tinkering.
Also worth noting if you’re trying to learn from my experiences is that I used an appropriately sized hole saw bit to cut my holes. The tighter the hole the better. I believe I paid about $10 for a hole saw bit that’d cut my plastic containers to the size of the PVC stem. Totally worth the investment.