Backyard Aquaponics
A place to discuss aquaponics

[align=justify]While we have settled on a general ratio of 2:1 growbed to fish tank volume to produce 5 - 6 kg of fish per 100 litres of water, it is simply a rule of thumb.

In practice, the number of growbeds that can be supported by a given fish tank volume will be determined by the nutrient levels that are generated in the fish tank.......the more fish, the greater the growbed volume......and vice versa.

There's also a direct relationship between the effort required to manage a production system and its productive capacity. If you want to reap optimum harvests, you have to manage the system narrowly. If you are prepared to forgo some of the productive potential of the system, you can probably sleep a little easier at night.

Vivienne Hallman, a Brisbane scientist who developed a simple aquaponics system several years, produced 17 - 20 kg of Silver Perch per year in a 4000 litre tank. The attraction of her system was that it was largely bulletproof as far as the fish were concerned......no pumps to fail, etc. She got nutrient rich water with which to water her salad vegetables - the fish were a bonus. You can read more about her efforts at http://www.cityfarmer.org/fishfarm.html

Joel has always stressed the belief that it should be kept simple and, for backyard food production purposes, I agree.[/align]

That what i was getting at garry, you just worded it better ultimatly a larger volume of water will give more stability and margin for error, and the planting density will rely on the number of nutrient producting fish.

Don't forget, systems will "grow" in ratio with time. ATM i have 40 jade perch in 1000lt. i'd estimate that they weigh 100g each at most (totaling 4kg) which are barely supporting three silver beet plants and a couple of peas. but with the right feeding i'm hoping to have them nearer the 750g mark by christmas, whcih will mean that i have 30 KG off fish!

Make sense too, the plants are going to grow more in summer and there will be more nutes for them

Strange how it all works together hey, when the fish feed less in winter, the plants are also growing less... Well thats what I try and tell myself as I'm throwing handfull after handfull of feed to the fish at the moment, and the plants are going crazy, though it is a mild winter.

yes, 2:1 ratio is the recommended ratio of growbed to fish tank for maximum stocking of UP TO 6kg per 100L.. One thing to keep in mind if you have a flood and drain system is that during a flood you have less water in the fish tank and you take this lowest level during a cycle as your tank volume when working out how many fish you may want...

Definately easier to have less fish though, it's way less stress, but also not as much fun as living on the edge.......

All my spring flowering natives in the garden are flowering at the moment and have been for the past 2 or 3 weeks, some of the winter flowering ones never bloomed at all. Definitely a mild Winter here in Perth...

Hi all - I have been away from my system for a little while (someone was feeding my fish) and have noticed what looks like pests eating into my veges, so much so that the tomatoes and chilies are buggered. Does anyone have any ideas?