Backyard Aquaponics
A place to discuss aquaponics

Hello all! I'm looking for some advice on designing a large aquaponics system. I'll be helping a local jail here in the Philippines set up an aquaponics garden. The jail adminstration thinks it would be a neat project that the inmates could maintain and learn some livelihood skills in gardening and aquaculture. They have a derelict old concrete fish pond, but we have a quote on fixing it. It's 14.63m by 4.87m by .75m (so about 53,000 liters). There are 4 small concrete supports in the middle meant to support a small hut or platform. I don't know what we'd use it for, but maybe we'll build one if we get enough budget. Maybe raise some ducks for extra nutrients in the system?

So, I'm basing our setup off of the demonstration aquaponics garden that I've been working on (http://www.backyardaquaponics.com/forum/viewtopic.php?f=45&t=28286). So if we stock 5 tilapia per square meter, that's 250 fish (we're stocking low because it gets hot here and we're worried about dissolved oxygen). I figure maybe 30 x 200L blue barrels on a flood and drain system filled with pH-neutral river rocks. If we just line them along the side, that would practically cover all the sides except one--maybe we'll have to line them up in the open space behind the pond instead. That would only be 6000 L of growbeds to about 53,000 L of water, but that's 24 L of growbeds per fish. Do you think that's enough?

Tough to get a feel for the size of the area around the tank in relation to the blue barrels. Will you have room to harvest without getting into the water?

You could build a platform for some filtration or more grow beds on the posts as long as the weight wouldn't compromise the bottom of the tank.

It's usually not a good idea to have poop from warm blooded animals like ducks in the system because of potential disease issues. I know that's not uncommon in green water culture so it may be accepted practice in your location.



Yes I think that will work but might be pushing it just a bit at first. I'd start with about half that number of fish to get things going. I'm assuming you will harvest the fish at about 1 lb or roughly .5 Kg. The amount of filtration needed in the form of grow beds is related to the final grow out size.

I'm not a Tilapia grower though so take the advice with a grain of salt. One thing I'm not sure of is the effect breeding by the Tilapia will have on the population density .

Yeah, you're right, we'll have to watch the breeding, but here they harvest the tilapia between 4-6 months, so hopefully we'll keep it to a minimum depending on the variety we get.

And yeah, the space directly around the FT feels a little limited. I'll check again when I visit, but I think we may have to put the grow beds in the vacant space on the far end of the FT that you see in the picture.

I'll look into putting some filtration on those platforms.