Backyard Aquaponics
A place to discuss aquaponics

I think the hammock approach is a fairly cheap option.
The 2`x 8` tomato hammock i built last year is fine with 200kg of wet compost. Just a single layer of weed barrier fabric holding the weight
Wouldn`t take a great deal to convert the design to hydroton filled flood and drain..gravel might be a bit heavy though.

A 2x4 timber frame, hardware mesh for strength and a liner.

Hex,
Got any pictures of said hammock you could post?

It isn't so much the media that is so heavy but when you flood you have the weight of water plus media, that gets really heavy.

Ok anyway. Here is the price difference I worked out for aprox 600 gallons worth of grow bed for my two different options I looked at.
12 blue barrels (that would be 24 half barrels) and the assorted stands and plumbing needed would come to about $1080.50 US the way I was looking at doing it. That is about $1.80 per gallon of grow bed.

The pallet stand plywood framed liner beds I was looking at doing, I would need 4 of said beds to get my aprox 600 gallons worth would come to aprox $648.06 for all assorted plumbing, framing and liner. That is about $1.08 per gallon contained.

Grand difference between two methods, $0.72 per gallon or $432 total difference on project.

Now if I could work out how to have the grow beds in the ground, same as the pond/tank, then the liner gets to be a really cheap option. I just can't figure out how to suspend gravity so that the drains will work.

Bathtubs seem to be pretty good in terms of cost. About the same price as a blue barrel, but much larger volume, drainage system already present, no bowing out at the sides etc.

Bathtubs are great if you can get em, I haven't had any luck getting my hands on any used tubs.

TCLynx, why not use standpipes through a 90deg elbow and drain from the side. Sure, it'll leave a few inches of water remaining after each cycle but I don't see that as an issue. 1 - the water gets replaced every cycle so it shouldn't stagnate, 2 - if your system stopped there would be some water left for the root system until the pump restarts.

my 2c worth

derekh,
I'm a little confused as to what issue this suggestion is to help with? Barrels or liner?

I'm pretty happy with how I've got loop siphons going on my barrels for the barrel ponics system I set up. I'm not sure how a stand pipe with an elbow out the side of a barrel would make it work any better.

For the liner? Well I still don't quite get it? I was planning to install bulkhead fittings through the liner sealed to a bit of flat plastic so they don't leak. I figured I'd come out the bottom and do a regular stand pipe bell siphon as well as a separate standpipe overflow.

Unless you mean putting the liner in ground but how would it work to drain the GB up to the surface of the tank? The water level in the pond/tank has to remain within several inches of the ground level or I will risk the sides caving during heavy rains. If the GB is sunk around 12" into the ground then it won't really work to drain it into the pond/tank even if the drain comes out the side. I've been thinking about a sump tank but with the heavy rains we get here during some times of the year, any not full container sunk into the ground is going to pop out!

Here you go TCL, theres a few pics of it in this thread..not much detail but its a simple design.
http://backyardaquaponics.com/forum/vie ... c&start=90

The bed can be used as-is with hydroton (with a trickle/drip feed), the only problem is getting even coverage of the medium.

TCL, I misread your question, I didn't realise you were asking about an inground liner. Pls ignore my comments.

TC, my plans are to have a bed lined with mesh rather than pond liner, using the bed like a trickle filter rather than flooding it fully. If you had a wood framed bed with metal mesh underneath draining into your lined pond (using a ramp?) that might be cheaper than liner-ed beds.

My price issue is more with the plumbing, framing, and gravity than it is with the liner itself. Liner, gallon for gallon seams a heck of a lot cheaper than any other method I have so far looked at.

As to your mesh. I love those patio designs! I still think flood/drain has some advantages over trickle due to the challenges of even distrobution and clogging.

Yep, the sub-optimal distribution is a downside.

What kind of liner are you looking at? All the high quality liners I've seen are like $150-$190 for a 15'x15' piece. With 1 foot overlap on the sides you'd have 13' to work with in each direction... if you make it 3' deep then the bottom can be a 7'x7' square... 470 gallons. Is this how it works? Won't you need some extra materials to complete the sides, to hold the plastic down or whatnot?

Oh and another idea instead of pallets. How about tires filled with compacted dirt? People use this method to build Earth Shelter homes. Lay the tire where you want it, fill it with dirt, smash the dirt in with a sledge hammer and keep adding dirt till it won't take any more. I think they would wear better then pallets since pallets are made of untreated wood (at least I've read that) and would rot over time.

When I first started visiting this forum I remember seeing a member's system who had a lot of rammed earth tires in his landscaping and I thought it looked pretty cool.

You`d have to be careful with runoff getting into the growbed as tyres contain cadmium.
I shudder to think that some people actually use them for growing potatoes

F&F uses a lot of them.

I've also heard of growing peppers in stacked tires because the black sides heat up from the sun.

They do tick a lot of boxes, they`d probably be ok for non edibles.

The planters made from a car tyre with the hub as a base, like a poor mans grecian urn were quite popular when i was younger.

An old tractor tyre could be a cheap option for a flowers-only growbed support but its probably not worth the risk for veg.
You`d have to use ornamental fish too