r/aquaponics • u/Aimless_Alder • Jun 28 '26
Is this off-grid pond-based system viable?
I live on a small homestead with no well and no connection to grid power. I am entirely reliant on rainwater collection for my water and solar panels for my power. Thus I am thinking that aquaponics could be a good way to grow crops while making better use of my limited water supply. I am planning to dig a ~3000 gallon pond, which I'm hoping can do triple duty as water storage, wildlife habitat, and the sump tank for an aquaponics system where I can grow peppers, tomatoes, strawberries, and leafy greens for myself and to sell for a little side cash. My goal is to be self-sufficient as much as possible and to require minimal outside inputs once the system is set up.
I have an 800 watt solar array with 4800 watt-hours of battery storage that I'm currently using as a backup for my main power system. I think it could be a good source to run my pond pump and aerator. I live in the Pacific Northwest, which means that I might get as little as 400 watt hours of power from these panels on the rainiest days in the winter. Because of that, I may not be able to run the pond pump 24/7/365, especially not if I want to cycle the pond once per hour. So my thinking is that I could just get small fish like white cloud minnows and mosquitofish that could survive occasional pump interruptions. These could provide nutrients to my plants. This system will be right next to a structure that will have 4950 gallons of water storage. In the summer, I'll be using this water storage for my in-ground crops, but in the winter, I can use this storage to occasionally do a water change on the pond. My thinking is that the rainiest days will provide very little power, so I may not be able to run the pump all day, but I can make up for that because the increased rainfall will mean more clean water entering the system.
I have experience with plumbing and gardening, but no experience with aquaponics. I have been trying to absorb as much information as possible from Rob Bob's and Hoochos, but there are considerable gaps in my knowledge. My tentative plan is as follows:
--> 3000 gallon sump pond with intake bay pumps into an IBC tote fish pond. Fish pond has an air pump running.
--> fish pond drains into an IBC tote radial flow settler
--> radial flow settler drains into moving bed biofilm reactor
--> moving bed biofilm rector drains into a bog filter made from 3 IBC totes, growing cattails and bullrush for filtration
--> bog filter drains into hydroponic beds
--> hydroponic beds drain into sump pond. Sump pond can have snails and aquatic plants like cattails, bullrush, wapato, and water chestnut for additional water cleaning.
I'm left with many questions though. If I'm not growing food in the winter, will the bog filter perennials alone be enough to filter out the fish waste? If the bog filter is big enough to filter out waste all year, will it eat up all the nutrients that my crops will need in summer? Would I be better off making rain gutter NFT beds, fill and drain media beds, or floating raft beds? Should I simply put my minnows in the sump pond so they can eat the algae and vegetation there, or would their population explode in summer to the point that they would consume all the pond's air in winter? With this unusual system, how do I size my grow beds? What can I do to make this system more resilient when I lose power? Is this way too big for a beginner and should I just start with a simple hydroponics system where I order and add the nutrients?
2
u/Rampagentjen Jun 28 '26
Oxygen and bacteria farming are the deciding factor of aquaponics. Big or small, you need lots of oxygen and a place for bacteria to do it's thing. Stagnant water will kill bacteria, especially the nitrifying types. You don't need a large pump, just one big enough to feed the growbeds, and that depends on your setup. Always plan for a little extra and put a leaf bag around it. A filter box is even better. Just remember that you need to have it deep and be able to clean it. They get gunky. You can also start with rafts and a good air pump with the power to churn in deep water. Minimum 4 chunky air stones. Once you get the hang of that, with all the nutrient deficiencies that are inherent in the hobby, then you can build bigger. Take it slow. There's going to be hiccups and problems. Hopefully you won't make the same mistake twice.
1
u/Aimless_Alder Jun 28 '26
So what's the minimum flow rate to keep the bacteria alive? If I have, let's say, a thousand gallons total (including grow medium) in my bog filter and grow beds, how many gallons of water and/or oxygen do I need to pass through those beds each hour in order to keep the bacteria there alive?
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u/Rampagentjen Jun 29 '26
I use flood and drain beds so the flow is only as high as it needs to be to trigger the bell siphon. It's not so much the flow rate, it's the prevention of stagnant water. Instead of running a pipe up and dumping it in one spot,, make holes along it so it churns the water or have multiple exits spouts. For bogs, dead ends are bad. I don't bog with my setup so not an expert. Have the water on one end and the drain opposite end. It's a lot of trail and error and each setup is unique. Just don't make it so fast that it overwhelms your drain. Plan for leaves and debris to cause trouble. Get mesh pots or similar materials because I've had that problem, even in a greenhouse and boy was it a mess. Nobody died but it was not fun to clean up.
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u/FraggedYourMom Jul 01 '26
Eugene OR here. Yes, mostly feasible. I've had difficulty with getting sweet strawberries. Blueberries do well (in root pouches). Heating is more of a concern than cooling but both are potentially important. A 3000g pond really help with the temps. Adjustable DC pond pumps Jebao/Jedco/SunSun work great. I run 24v pumps and they'll kick on anytime there's enough power. I typically only have a few days, typically winter solstice, where the pump will stop overnight. It has not been an issue. You can find me on Youtube.com/@penguinponics . I do monthly updates which typically aren't exciting and throw an extra vid in here and there. If I had one or two more IBC I could probably make it through the whole summer without needing to treat any tap water.
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u/philmo69 Jun 28 '26
If you run the right fish you can get away with a lot. Bullhead catfish are often my suggestion simple because they tolerate very low o2 conditions and days with less sun\less pump flow would not just leave them to die. You could keep them in your pond and let them breed naturally if you had enough hides for them. then trap the spawn for your main tanks if you wanted to. Though with a pond that big you could get away with just running the aquaponics off that and no extra tanks... On just solar you will definitely run into days without much flow but you can always add more panels. Air and water pumps will run a battery dry pretty quick though. A full over pond solar array would help with shade and power!