Backyard Aquaponics
A place to discuss aquaponics

Its also great to see inside your fish tank. Like you, I can't wait to see fish finally in it

That will be really interesting to see how much heat you get off the exchanger. Sounds promising.

Hi Jamie, I used a semigloss Rustoleum. That brand has been used for metal since I was young. I have seen it age outside for a lot of years and I am impressed with its durability. The solar exchanger has stove paint in flat black. That is another paint I have seen stand the test of time. I did white in the fish tank because I had that color. The flat black helps capture the solar heat.

Hi Doug, system is very cool, looking forward to hear how the heater goes. Do you think the rustoleum will hold up underwater OK? What about powder coating, can that be done with copper?

Update, two weeks from tank fill and counting. I have been working on the system with the goal of filling my fish tank by the end of Feb. (maybe first week of March). Second week of March I have contract work to do offsight and no time for BYA.

I have built the grow bed from pressure treated (P/T) 3/4" plywood and P/T 2x12" board. It is 32' x 34.5" x 11.25". I also assembled my pump system which consists of an 1800gph and 1200gph pump in tandem with check valves, so I can operate either or both. With 10 feet of head, they will provide 900gph & 600gph respectively. I power them from 12 volts using a 150watt cont./300watt peak inverter. I use solid state relays (SSR) to apply 120vac to each pump. The pumps are 145 watt & 100 watts.

I have provided a photo of my testing. I have no pride, I am that messy when working. I have a 'Killowatt meter" hooked between the inverter and pump to monitor load power. I have a 10 amp meter monitoring battery current. An interesting thing in this was the power factor of the pump loads. It was approx. 0.11 (resistive loads are 1.0). The pump motors are very inductive loads, as expected. Everything worked fine and I was turning pumps on/off with a logic level as from a computer I/O port. Ready for tank mount.

Next I assembled my filter. This is an upflow filter of the same type I use on my outside ornamental fish pond. You can clear sediment from the stock watering tank(100 gallon) from an 1.25" drain plug at the bottom of the tank. I added a gate valve and flex hose to the drain for flushing. The water from the fish tank enters about 6" from the bottom thru 1" PVC pipe drilled with 0.25" holes every 1" along its length. Then the water passes up thru a plastic panel with 0.25" holes in a 1" pattern. The flow rate is small and well distributed over the whole area by the panel, so sediment does drop to the bottom fairly well. Works great in my outdoor pond. Cleanout is done monthly. This was sold as plastic peg board for hanging tools (2' x 4' for $12.96 US). Then comes a 8" layer of lava rock (sold for barbeque grills) and 2 cu ft of plastic media high surface area for bacteria growth (235 sq ft/ cu ft). The lava rock/plastic media/filter mat/bottom of grow bed floating styrofoam sheets gives massive surface area for bacteria (about 800-1000 sq ft?). Then another layer of plastic panel and finally a level of washable filter mat. Then the water flows from 1.5" pipes into the growbed. The photos show some of these elements and the end of the growbed. Damn, the spraybar pic was too large; I will try again later with that shot.

Here is the spray bar. BTW, the photo of the divider panel in the last post on top of the filter tank has two posts sticking up. Those are supports that rest on the bottom and handle the weight of the lava rock.

Hi again Deebee:
Are going to line the grow bed with pond liner? Be careful with the treated wood - it will kill your bacteria (probably the fish too) like nobody's business.

Absolutely DeeDee:
I have fish pond liner for the growbed. It was expensive, but definitely a safe material. No P/T will touch my veggies!

Thanks for the warning. P/T would be bad for fish/veg/me/etc.

Good - carry on then. The plastic pegboard is a neat idea!

I used P/T to build the greenhouse in large quantities (even the wall studs). Very expensive! But the humidity in the greenhouse was a factor I worried about. I had a book on solar greenhouses that went back and checked on solar greenhouses built 10-12 years earlier and they were rotting out. Many had been rebuilt to some extent. I want this unit to last my lifetime (not that long anymore I guess...but I assumed an optimistic number ).

Wow, you clean your pond filter monthly? I use the same style filtration, and consider cleaning it out once a year. Then I usually get too busy and forget. I have to clean the pre-filter on the pump about once a month, but not the main tub of lava rocks.

Nice neat system. I wish I had access to all those materials.

Thinking about your statement, I said it wrong.

I clean my filter once a year by removing filter mat and blasting with hose, then cleaning lava rock and washing bottom of tank.

Once a month, I open the gate valve until the water comes out more or less clean. A very quick flush (10 minutes).

My pond was massively neglected this summer because of our three month trip. Almost no feeding, a friend about once a week. No filtering and no water adding. When I came home, the water was low, but my fish looked happy enough. I was pleased and surprised. The pond is about 2500 gallons full and went down to 1000 gallons before I got home and filled it. Interesting.

Hi Doug,

I would love to know what you know about control systems.......your system is amazing.

One question though.......is your fish tank going to be deep enough at 11.25 inches? I've had fish jump out of a tank of similar depth (but much smaller in area).

Gary