Let’s take a look at what needs to happen in an aquaponic garden for everything to keep on living, growing and producing for you. Obviously the plants need to be watered, that’s a given, and the fish need to be fed. Regular feeding of fish produces waste products that will build up over time and kill your fish. It’s not pretty or fun to see. So the first big problem that needs to be solved is removing the waste from the water to keep those little critters happy, or at the very least … alive.
Now, if you’ve even looked into aquaponics at all you’re probably saying to yourself, ‘well, don’t the plants do that?’, or some variation on that theme anyway. If you are, then you’re right but there’s more to it than that. Successful aquaponic gardens are populated with a few naturally occurring bacteria that are essential to that success. These tiny workers need somewhere to call home and conditions that benefit their reproduction. Just like everybody else, they are looking for a safe place to call home & a steady food supply. Providing them a home is the easy part. Anything non toxic with surface area in the water will do quite well for them, mine love it! This is why you will see so many different things being used in aquaponic systems that are all generally referred to as the bio filter. I’ve seen everything from lava rocks to lego, clay pellets to river rocks and even some fancy scientifically engineered stuff to be ‘better than nature’. That’s a bad joke but we’ll just push past that issue for now. Building a basic bio filter into a no power aquaponic garden isn’t that difficult, but it does need to be done. I could make a whole playlist of video options for this but just be creative and it will probably work for you as a starting point.
So now that we have a bio filter in our garden the fish will be safe right? Nope. With a completely no power garden your fish face a few other dangers that all need to be looked after as well, or they will die. I’m not going to sugar coat this for you, that’s just how it is. Some of the other concerns include, but are not limited to: dissolved oxygen levels in the water, pH imbalances, ammonia spikes from low bacteria levels, greater risk of water borne diseases such as ich plus a few other issues I’m probably forgetting at the moment. Some of that is as easy as the bio filter, in fact if your bio filter is almost always getting a ‘fresh’ supply of dirty water it will take care of a few of those for you. Dissolved oxygen and ammonia spikes at any rate. So here is the next big question. How do we keep water flowing without electricity?
It can be easily said that there are vast numbers of ways to make this happen but they are all varying degrees of annoying, unreliable or just plain hard work. One of the first solutions that comes to my mind is some form of a water tower to do the trick. This adds its own difficulties and challenges but hey, we’re building a large scale no power aquaponic small farm here so it’s not going to be quick or easy. Just saying. To avoid the water tower one could perhaps make use of a very basic wind turbine and use that to drive a rope pump. Another solution with its own unique issues and challenges. Let’s take a better look at both of those options, shall we?
What are some of the issues with the first option of a water tower? Well, as a tower that suggests it will need to be built to some height and moving water uphill is a problem for nature. Gravity doesn’t really play that game. Another issue is the large amount of water that it removes from the fish tank all at once. Rapid raising and lowering of the water level can cause the fish huge amounts of stress and stress is a killer. Best to avoid it whenever possible. Good life strategy right there but back to the topic. Creating an overflow drain in the fish tank, more on this later on, that goes to a secondary sump tank can solve this problem if done correctly. I would think a sump tank that holds at least as much water as the tower plus half again would be about the right size. This will ensure that your fish have a steady ceiling height at all times and keep them a little happier. Happy fish are healthy fish! The height of the water tower is basically easy enough to deal with as well, just make sure the bottom of the water storage on your tower is above the top of your growing beds and make sure they are taller than your fish tank that has it’s sump tank even lower down. Gravity will do everything but put the water into the tower for you, not bad. Just make sure you build that tower base strong, water is a lot heavier than most people think. Options for getting the water from the sump to the tower are unlimited. Buckets, rope pump, DIY piston pump, cast iron cistern pump (old west style can pull water up 25 feet!), water screw … I could go on here but I think you get the point. Next!
The other solution mentioned was the use of a wind turbine and a rope pump. Again, any style of hand pump can be made to work here with some creativity. While there is a very typical picture that comes to mind when we think of windmills or wind turbines that doesn’t mean they are the only ones, or even the best ones for that matter. In my library of previously loved books I have a copy of ‘Practical Projects for the Handy Man’ that was first published back in 1913 by the editors of Popular Mechanics Press. In this gem of a book is a simple windmill that works no matter which way the wind is blowing but doesn’t swing around like ‘standard’ wind turbines do. I’m not going to explain how to build one here but if you’re interested you should definitely look into them, very cool & super basic. 1913, enough said! If you build something along those lines it would become fairly simple to attach a pulley for a rope pump and let the wind do the work for you. Wind moves the water up & gravity moves it down. Excellent, no electricity so far!
Next we need to get that water moving into, and out of, those aquaponic garden beds or why are we building all of this?!? This is a good time to start thinking about installing the bio filter. As the water leaves the tower and runs into the garden is a GREAT time to make sure that it’s been converted from fish waste into plant food! Now is also a good time to figure out what style of grow bed you will be using since that will make a big difference to how you want to deliver the water to the plants. For a floating bed or raft system simply allowing the tower to drain, through the bio filter, into the beds at a set rate would be fine. Adjust it as needed to keep the water moving all day, or at least in between times you can refill the tower, and you’re good to grow! More or less, we’ve still got a couple of important points to go over so don’t run away just yet. If you are growing with a flood and drain bed in mind then water control will be your personal nightmare from here on out, just my opinion. The easiest way out of that trap is a quick fill with a slow drain. Our three main goals with the water are to keep the plants hydrated, but not swamped, and to keep oxygen levels up while keeping the waste levels down. With a quick fill of the beds the water gets plenty of oxygen as it rushes through all of the grow media, and it gets even more with the slow drain out as it will always keep the top of the fish tank in motion. Waves = oxygen for the fish. This type of bed also provides a second area for bacteria to live which will help prevent those evil ammonia spikes.
Getting back to the overflow drain in the fish tank for a moment here if I can. These sound more difficult to make than they really are. There are many great videos out there on exactly how to make them but the basics of it are simple enough to cover here in the blog. The goal is to collect all of the solid waste from the fish, the poo if you prefer, and to draw it away from the main tank. A good goal, after all nobody wants to swim around in poo. Some aquaponic gardeners have attached various fittings to aid in the collection at the bottom so explore your options and see what you like. Since my fish are all fairly large I simply leave the bottom of my drain pipe open and it seems to collect most of the waste. The top end of this pipe needs to be attached to a ‘T’ fitting so that the water can be directed through the sidewall of the tank and into the sump while still leaving the top of the drain open. As for getting the pipe through your fish tank sidewall I prefer the rigid nature of bulkhead fittings while others seem very fond of Uniseals. Whatever you can find that’s non toxic and does the trick … works! If this is setup correctly, it should create an overflow that draws the water and debris from the bottom of the tank while not making the vacuum suction that would drain the fish tank entirely. VERY important that the top of that upright drain pipe is open, that’s not a fun mistake to make.
The last couple of things I should mention here are water changes and fish food. Both of these are often overlooked in many aquaponic systems but vital to the overall health of your garden. In the case of a ‘No Power’ style aquaponic garden, your fish are basically in a fishbowl and as the water evaporates not only do levels of the fish waste become more concentrated but so do the levels of assorted hormones that the fish release into the water as part of living day to day life. Not a problem if you are trying to keep your fish small but it can become an issue if you want significant growth from them. Sure, a top up of the fish tank will thin things out again but none of it is removed so ultimately it just keeps adding up. As often as your water supply will allow for, you should remove at least 10% of the overall systems water BEFORE adding more fresh water into the system. If you must use tap water, try to allow it to sit in the open for 24 hours first to naturally remove the chlorine. That stuff can wipe out your bacterial colony so fast it will make your head spin, avoid whenever possible. The final thing is, as I stated above, fish food. Let me just leave you with this thought about your choice in fish food. What they eat becomes what feeds the plants that you eat. Anything that goes into that water could make it’s way into your food …
Thanks for taking the time to check out my thoughts on a larger NPAG for small farms. I hope it helps or at least entertained you! Blessed be & many happy harvests to you!
JT Bear
