Backyard Aquaponics
A place to discuss aquaponics

My first system is nearing completion. I've spent much more on it than I wanted to I built it so that I could add more grow beds without upgrading the pump.

The fish tank is buried 2 feet deep to take advantage of the earths insulation properties but after a few nights the temperature of the water has already dropped to near freezing. They say that heating the water is easier than cooling the water. I've been exploring passive heating systems like a solar water heater or an adaptation of a solar box oven.

The location I've chosen isn't ideal for the winter months it get little to no direct sun this time of year but I chose the spot because winters here are short and summers are long and temperatures regularly exceed 120/90 F HI/LOW. I was thinking I could use some reflectors to redirect some sun light back towards the plants. I wonder if anyone has attempted anything like that.

If you have any advice it would be greatly appreciated.

Looks familiar.

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Hey Tlrob... Don;t worry so much about trying to heat your water with solar like that, it's just not going to work because your beds act like giant radiators. Look at stocking a fish species that will suit your temps..

I realize that a lot of heat will be lost through my grow beds until I can build a green house. But my solar oven cooks at 250 degrees F during the winter and over 300 after February. I don't expect to get the temperature to 70 degrees or even 60 degrees but the warmer the water temperature the more active the fish. Active fish equals more ammonia for the bacteria and more nitrates for the plants.

In addition most fish that can tolerate the cold cant handle the long heat of the summer. I'm starting out with gold fish because they are cheep and I will kill them I'm sure but I do eventually want to raise something edible.

How long do you think the plants can go without water? I turned the pump off while I was out of town and the water is about 10 degrees warmer.

you could shut your pump off overnight to help with the heat retention, but i wouldn't want to do it longer than that.. not for the plants, but to filter your fishtank water..

My system (link in my sig) is laid out fairly similarly.

I didn't order enough expanded clay to fill both grow beds. That stuff is more buoyant than I am so I purchased some decorative pea gravel that said it wont decompose. Not sure if that means its pH neutral so I'm going to have to test it. I don't have vinegar so I thought I could rinse some rock and soak it over night and test the water to see if it has effected the pH. But I don't think that the change would be very large unless there was a lot of lime stone. I guess I'm going to the store for some vinegar.

Don't worry I took video of the construction of the main components. I am editing out the swears as fast as I can. My goal is to post the first video on youTube by the end of the week.

Here are some pics.

That 50 gallon Rubbermaid would make a great additional grow bed you know.

I plan to grow duckweed and a few greens on a raft in that one. Someone also gave me another 55 gallon drum with the top cut off. I haven't decided what to do with it yet.

You might be able to keep some heat in by installing plywood around the base or at least 3 sides to keep air from circulating

I added some fish a few days ago. 10 feeder golds for a dollar. They haven't eaten yet but nitrates are already at 5.0 Ammonia is a little over .25. And no deaths yet. I don't have a nitrite test yet. But I do have a Phosphate test. No phosphates but I think that's something I have to add.

Right now I'm just using pond food but when I get my "eating" fish and crayfish I definitely want organic food. I plan to grow duckweed and possibly black soldier fly larva but I don't think they will provide all the nutrition my fish need. Crayfish are a whole other matter. Do they eat duckweed?

What do you feed your fish and crayfish?

I was thinking about how to integrate the 50 gallon duckweed tank. It occurred to me that I could use it as a reservoir to regulate the water level in the tank.
What I want to happen is when the fish tank gets below say half filled the float valve is opened draining a portion of the water in the duckweed tank to the fish tank.
I would have to make sure that the float is buoyant yet heavy enough to open the float valve.

It just occurred to me however that this design might cause the fish tank to overflow when the grow beds siphon back to the fish tank. But if I have one or both grow beds siphon into the duckweed pond it wont. But the duckweed needs still water.