15 How Much does this Cost Under 1000

Heres a run down of the amount I paid for this system, with suggestions on how you can reduce costs even further.

Tanks - $440 - I was able to get the Rubbermaid stock tanks at a local farming coop for $70 and $80 for the 50-gallon and 100-gallon tanks, respectively. I think youd need 3 IBC units to make something similar out of IBC, so that wouldnt save much cost. However I understand that its possible to get 55-gallon barrels for free from local beverage processing plants. The downside of 55-gallon barrels is youll have to spend more on plumbing, youll have a lot more cutting to do, and the end result will look like hack-sawed plastic. But free is free.

Hoop house - $100 - If you use pressure-treated landscape lumber for the base, 3 mil sheeting, and 1/2" EMT conduit, the total price rolls in at around $100. You could slightly reduce costs for the frame by using PVC. Or you can decide you dont need protection at all, if youre in a climate that doesnt require protection from excess sun, rain, or cold.

Pumps and timer - $110 - I was able to find my 800 gph pump at a local hydroponics store for $60, and you can get an air pump sufficient to aerate 100 gallons for $30. Tubing and air stones round the total amount upwards to $100. One option is to dispense with the air pump, if you pump some of your water over the surface of the fish tank, oxygenating the water the way a pond fountain does. There are ways to use wind power to drive something like a rope pump, but I dont think that is cheaper than an electric pump (though awfully fun to make). I do use a timer to turn my water pumps off at night, which is another $5-10.

Plumbing - $100 - I used 3" pipe for media guards (4 feet), 2" pipe for bells (4 feet), 1" pipe to connect the tanks (10 feet), and lots of 3/4" pipe for upstands and drains (10 feet). Add in the elbows and adapters, caps, and o-rings and youre up around $40. I used garden hose that is drinking water safe to carry water from my sump tank to the grow beds, so two 50 foot lengths, adapters, and Y splitters ran me $60. You could reduce cost by having a simple standpipe and using a timer to turn the water on intermittently, though your water pump capacity may need to increase. As for plumbing between the sump and the beds, you could plumb that with PVC pipe and elbows. If you find a cheaper way to do it, after tallying all the costs, go for it.

Grow bed supports - $60 - I used cinder blocks (16 @ $2.50) and 2x6 planks (4 @ $5) to support the grow beds. If you are able to dig your tanks down into the ground, you can cut back on the number of cinder blocks required. If you can find such materials second hand, thatd be great.

Floating Raft - $40 - I was able to get a 2x8 sheet of 2" extruded polystyrene for $15, and the 2" net pots cost $0.39 apiece. I suppose you could come up with some kind of wood float supported on empty water bottles and used (drilled) plastic containers.

Media - $ to $$$ - If youve got a pile of 3/4 gravel out back, this could be free. If you fill all four grow beds with Hydroton (@ $40 per 50L bag), you could be spending about $600.

So the basic system as Ive got it here (including a floating raft bed) is $850. I love Hydroton, but I know of a friend who got an entire truckbed full (1250L) of expanded shale for under $60. So you can create an extended-season, vegetable-growing, fish growing water storage system for under $1000.

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11 Media Options

Winter seedlings in river rock, transplanted to Hydroton in spring
Fish waste isn’t the perfect fertilizer. Waste is mostly ammonia, which is nearly useless to plants and deadly to fish. The perfect fertilizer is nitrate. The ammonia in fish waste becomes nitrate when enough beneficial bacteria have done their magic. "Media,” like rocks and hydroton balls, are where the beneficial bacteria like to live. It so happens that “media” does a nice job of physically supporting plants and roots.

When it comes to media, I stand on the shoulders of giants. Those who have gone before me assert that you need something that is ¾” in diameter, on average. Dirt, sand, and small pebbles will clog and develop oxygen-deprived zones when used as the predominant medium in an aquaponics system.

What is the best media? It depends. The major options are gravel, river stones, hydroton, and expanded shale /slate.

• Gravel is cheap, maybe $10 for 50 gallons. But it’s heavy and hard on the hands. Depending on where it comes from, it may not be pH neutral.
• River stones aren’t quite as hard on ones hands as gravel, and are also cheap. They are also heavy and may not be pH neutral.
• Hydroton is the lightest option, it’s pH neutral, and it’s a dream to plant in. But Hydroton is only made in Germany and China, and it costs about $200 for 50 gallons (sold in 50L bags), assuming you can find it locally and don’t have to pay shipping. One downside to Hydroton is that it will shift under pressure, like when a heavy wind blows though your garden.
• Expanded Shale and Expanded Slate are pH neutral and almost as light as Hydroton. These products are both made in the US and are primarily used in construction and landscaping. If you can find a local bulk supplier for the ¾” product, the price per unit volume can be as inexpensive as gravel. But if you have to get it shipped, it is about as expensive as Hydroton.
  
  I’ve used river rock and Hydroton, and I loved the benefits of Hydroton. When I moved to my outdoor system, I divided the river rock from my single initial growbed across the four growbeds, filling the top with Hydroton. I figured the expensive loveliness of Hydroton would be wasted in the bottom-most sludge region of my growbed. And perhaps that layer of river rock anchored plants that might otherwise have toppled.
  
  If you’ve got enough media hosting beneficial bacteria, you can consider converting one of your growbeds to constant flood (with or without floating raft). The rule of thumb I’ve seen for home systems is 3-4 media beds for each constant flood bed. Constant flood beds can be good for starting seeds, growing duckweed, or growing leafy plants like basil and lettuce.

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