Today I've just put together the cheapest and simplest flood and drain aquaponics system I can imagine. The only simpler aquaponics system I can think of is floating some plants directly in the fish tank.
My motivation was 2 fold
1) have a system away from the chickens hungry beaks
2) demonstrate how simply and cheaply you can get in to aquaponics.
It is made from
- 2 broccolli styrofoam boxes free from supermarket or veggie shop
- river gravel left over from my main system. I can't remember how much this was, but I do remember it was cheap, and the landscaping place would sell it in any volume you wanted.
- a small 200L/hr 5Watt aquarium/pond pump you can pick up for about $13 from bunnings
- a timer I had laying around, or you can pick one up from kmart for $7
- pipe up from pump to grow bed, I had laying around. You could buy some pipe for $6 or less
- a rubber band as a pipe o-ring seal and something to fasten the pipe to pump as they weren't designed to fit together
- the optional pipe out of the grow bed overflow.
- a small hole poked in the bottom of the grow bed - free
- extension lead - not much $$
- drink bottle power plug outdoor protector
- some sticky tape
- I'll add a small goldfish later. they're about $3 when you only buy 1.
- poking device (aka screwdriver) to make holes in styrofoam.
- utility knife to cut soft pipe
It has 2 holes poked in the grow bed, a small one in the bottom over the fish tank, and a big one nearly at the top on the side to overflow back to the fish tank underneath.
With such a small pump, it takes about 12 minutes for it to fill, then about 5min to drain. I have the timer set to pump for 15mins every 30mins in the middle of the day, every 45mins in the morning and evening, and every 60mins at night.
Because I'll only have 1 small goldfish and it has a fairly large surface area per fish + the grow bed splashing, no air stone is being used.
Here's some pics
see, it's a little pump
very simple, water goes straight up to the grow bed. Note that I didn't wash the gravel, as you just do not need to. The water will clear up in a few days. Seeing as the flow of water out of the small hole in the bottom is slower than the pump puts it in, the grow bed fills up.
until it reaches the overflow hole poked in to the side. See that little pump has enough flow to flood the grow bed, though it takes 12mins. Note the lid with cut out sections provides additional strength to the box. Also note the box on the bottom is a thicker and stronger box.
Then when the 15min on the timer is up, the pump turns off and the water drains back down to the fish tank through the small hole in the bottom of the grow bed.
my outdoor safe power cable connector enclosure. No rain gets in, and drips that travel along the cords drip off at the bottom and do not enter the container.