Backyard Aquaponics
A place to discuss aquaponics

I have been reflecting on my AP design. I need to have fry already going if I am going to grow them out before next winter, but I have not even gotten my tanks in yet or the fish sexed. I was planning on growing 360 pounds of fish in a year all in one massive batch then doing a massive weekend of filleting and freezing. Now, however, my thought are turning towards always fresh.

What I was thinking was this. One large grow out tank, 4 or 5 fry tank and a breeding tank. Let the breeders produce a batch of fry every week and move them to one of the five tanks to get them big enough to put in grow out tank; keeping only the best 7 fingerlings. Then at the end of 9 to 11 months I would have 7 tilipia large enough to eat each week and fish of all ages ranging from fingerlings to full grown. This would let me go out to the tank every night and fillet my dinner fresh without having 360 fish ready all at once. Thus, requiring a smaller volume of water.

Another goal this would meet would be the ability to, perhaps, have my grow tank indoors where it could be heated during the winter.

I would like you guys thoughts (bad english?) on what the smallest system I could build would be and be able to pull this off. If 1 kg of food results in 37g of ammonia then I guess I need to figure out how many pounds of fish my system might hold at the end of 10 months; any idea? Then I could decide how much biofilter/grow bed I need.

Go here http://www.thefishsite.com/articles/136 ... of-tilapia to get a growth chart.

Assumptions:
- You stock fingerlings at 20g and harvest at 450g.
- You are able to achieve the growout rates in the chart, and experience no predation (poor assumptions)
- 20g fish are able to eat the same sized food at the 450g fish, and won't be cowering in the corner as the "big boys" all eat. (poor assumption)

Doing this at 30 fish per month to make my math easier, we know that on any given day, you should have 30 fish each at sizes 450g, 375g, 250g, 100g, 50g, and 20g. That comes to a total fishload of 37.35 kg. So 82 pounds of fish, 165 gal of fish tank, and 330 gal of growbeds IF you are a very very experienced and attentive fish keeper. 330gal of fish tank and 660 gal of growbeds would be better.

However, from the fishbones I've found in my pump, I will assure you that the big tilapia will eat little tilapia. If you want multiple batches of fish going at the same time, I would suggest setting up 3-4 systems with 100gal tank:200gal beds. Rotate harvest and populating. This also separates systems so that disease or disaster doesn't wipe everything out.

I like the idea of maintaining a "cycle of life" system, with continuous production rather than batch, but it may be more work and/or PITA. I agree with JP that several distinct tubs would be easier to manage, rather than keeping mixed sizes together or moving them around. If your mostly ready fish were segregated already it would be really easy to binge/purge/harvest them.

Check out this idea too:
http://backyardaquaponics.com/forum/vie ... 5971#35971

Thanks Janet! That gives me a starting place. I assume that the other 180 fish are under 20g?

IF it can be done in 165 gallons of water then I will use 4 times that amount. The grow bed volume should not change..

Do you think I could do this in 100 gallon stock tanks? 6 for the 20-450 gram fish and 6 50 gallon tanks for fry and 1 150 gallon for mating?

Very interesting Dave. I was just giving some thought to fluidized sand bio filters. Because I will need to be completely indoors during the winter I will not have room for the grow bed inside. Unless I do a vertical wall garden like on Gardening Australia. SO perhaps a sand bio filter and a wall of NFT chives or what ever is the highest nitrogen consuming plant.

Hey DDM, I was linking to the concentric tanks design, to segregate the different sizes of fish.

Regarding sand filters, I wanted to change from gravel beds to rotating biodisks, but haven't been able to do that yet. The round floor cleaning pads look to be too expensive and I haven't come up with something that would be as cool as those. I just carried 50 gallons of gravel and several concrete blocks into the basement this weekend and gravel is heavy.

Kale and broccoli are pretty heavy feeders and partial to cooler weather though I think they like bright light as do spinach and most flowering plants. Lettuce is a pretty obvious choice for indoor production as it doesn't require the really bright light levels, is great for fresh salads, is relatively compact but lettuce is a relatively light feeder. I have many house plants that do great with lower light levels indoors but they also are relatively light feeders. Then again, just because they survive with very little care doesn't mean they wouldn't take up lots of nutrient if it were available, I don't know.

Good luck with your planning.

Yes Dave gravel kinda sucks and as I under stand it has a surface to volume ration of 200:1 vs scrubbing pads with a ratio of 300:1. Also, what is Siporax and bio bales? These have a very hight surface to volume ratio. 10,000:1 and 800:1

Back to the vertical garden like in epp 35 of gardening Australia.
I may try something like this. Its a cage with poly fiber mat to hold in perlite. If I could replace the grow beds with something like this then I could have a 8 foot by 16 foot grow bed enclosed on the south wall of my building and only need to enclose a 4 foot area with plastic. Talk about a space saver! Also, TCL this would allow full sun. Having grow lights would defeat the purpose of creating a sustainable food supply.

Yes, the other 180 fish are the ones that are less than 20g. I figured on 30 fish per weight on the growth chart.

I would have your breeders in a 55gal aquarium so you can monitor them better. Things can get a little rough, and if you don't separate things, you can get your girls killed. Also keep a spare 55gal aquarium for R&R. And maybe another 30gal for the first month of life for your fry. They're mighty small, and would get lost in a big growout tank.

I would put 100gal of water in a 150gal stock tank. Tilapia are good jumpers, and having the water level down a bit allows some margin. Even so, I lost one jumper before I put the lid on. So if you had 12 150-gal stock tanks for growout, and stocked one each month with fry large enough to escape the pull of the pump, I think you could do very very well.

That's what I wanted to hear! Its do able in my shed. Thanks.
Sounds like I need 6 150 gallon grow out tanks and 6 30 gallon tanks for fry and 3 55 gallon aquarium tanks for breeders (male/breeding tank, Private tank or two for the girls).

Instead of grow beds I am going to use a small gravel bed for solids filtering (with worms and plants) and a bio filter with bio-bale (an 800:1 surface to volume ratio) to process waste with. Then pipe that to either a grow wall or NFT system with heavy nitrogen feeding plants.

Does anyone have data on how many grams of nitrates a plant will take up in a day?


This plan is coming together!

Oh, Janet, as far as aggressive males go I think I will trim their upper lip like you did.

My new mantra is to concentrate not on fish water volume but on filter and sump volumes, as those take up space faster than your grow out tanks would and the poo would become a menace if you didn't have the filtering up to that capacity. Start thinking about how you're going to house 2400 gallons (11 cubic yards) of gravel plus sump volume! Even assuming something more efficient than gravel you'd need a lot of plants to take up all that poo.

So to match 11 cubic yards of gravel you're thinking about 2.75 cubic yards of bio-bale? That would $3700 from this outfit:
http://www.wetdryfilter.com/bio-media.htm

Whew!

Actually I plan on using that easter fake grass stuff packed in a container; the clear type. It is almost the same thing. 5ea 50 pound bails would be 1 cubic meter.

The only thing that might beat that is thousands of feet of fishing line.

I plan on calculating how much bio bales volume will be required to process the ammonia for my full system based on the amount of feed I will be giving them.