Backyard Aquaponics
A place to discuss aquaponics

Hi everyone. First time poster, long time reader. I've finally decided to get a system up and running.

The first hurdle I ran into was how big to make it with the various constraints. A few hours later I realized it'd be much easier in a spreadsheet, and I thought maybe some other newbies could use it.

Apparantly spreadsheets aren't allowed here. So I'll link it on my website:
Aquaponics Ratios

It's tailored to raising tilapia because from my reading they are fairly hardy, and my lady-friend likes the way they taste!

It's in both english (for we Americans) and metric.

Comments are appreciated.

it's very interesting, it would be good to see if we could tailor it for other species as well.

All you need is harvest weight and stocking density for the species you want to use.

From what I understand the volume of grow bed and grow bed are pretty much constant across systems.

welcome tamo

everybodies systems run at different ratios of growbed volume to tank volume. It mostly seems to depend on what you can get hold of and how much space you have. There is an "optimum" or "ideal" ratio, but few systems match it

Oh yeah, welcome

Welcome Tamo... a very recent post was discussing just the sort of spreadsheet you have created.

Again welcome and look forward to your system

Tamo, what about if you tried the spreadsheet like this? here

I've tried to make it species non-specific

J, would not work for me!

is it missing the xls extension on the end?

is a zip file


waaaaah it won't work for me help!

Jaymie, looks good to me. I simply have no idea what normal mass/density numbers would be for an average fish.

I've finally fixed it (a naming problem at my end ) and I think it works now

Welcome Tamo!

I spent the longest time calculating and recalculating gallons and beds and fish. What it finally came down to is how much space I had in the sunroom. Now I'm playing with a spreadsheet, trying to estimate growth rates and how to stagger two crops of fish. For tilapia, I think what I'm coming to is that I should start the next batch of fry about the point that I eat the first smallish fish of the previous batch. That keeps my fishload more consistent.

I was thinking about growth rates this morning. It seems to me that since my starting fish weight will be significantly less than my ending fish weight that any grow bed design should be modular.

So as the fish grow you can add more bed volume to take up the increase NH4 production.

Or is that already compensated for in going from plant seedling to full grown plant?

It depends partially on whether you are producing in a batch-type system or more continuous flow. My plan is that once my plants and fish get established, to be continuously planting, harvesting, and pulling out fishies. I also hope to have a few breeders to keep new ones coming. I would be having to move fish from one area to another as they grow (breeding tank to fry tank, to fingerling, etc) but my hope is to try to move to a steady-state system where I am eating about the same amount that I'm growing both in fish and veggies.

If, on the other hand, you plant and throw fry in at the same time, then let both grow together, and harvest together, (you will probably still need to rotate your crops a bit, since they take less time to grow out than fish), this would probably work better in a place where you need to keep your system seasonal (unheated GH, etc.)

Only the nitrate is handled by the plant growth. You still need more bacteria as the fishload increases to handle the increased ammonia and nitrite.