Backyard Aquaponics
A place to discuss aquaponics

Hmmm... I think I just need a length of 4" PVC and a large endcap. I have lots of spare parts and some beach sand. There may be a trip to the hardware store tomorrow!!!

Something see-through would be nice so you can see whats going on.

One of those 3" dia x 4ft tall acrylic bubble tubes might ideal for a conversion, they usually have plastic goldfish floating in them and a rotary colour changer at the bottom.. ditch the plastic fish but keep the trendy light

Another diy sand FBF link:
http://www.sydneycichlid.com/fluidised-bed-filter.htm

There's a DIY design somewhere in my bookmarks that uses clear plexiglass as a box for a FBF, but I can't find it at the moment.

Overall there are LOTS of designs online for DIY FBF.

I gotta say... wow. This opens up whole new design possibilities mixing more NFT techniques, allowing for a higher density of plant growth. I'm envisioning a setup where the output of the FBF goes to a growing tray with 1 or 2 inches (5cm) of grow media. Impressive stuff.

I did find one page saying the straight-column design is the hardest to tune to the proper flow rates, and that v-shaped, cone-shaped, or such are easier to work with although harder to build.

Maybe you could make a small one in a 2-liter Coke bottle. Hmmmm........I wonder if that would hold a pound of sand.

JP, if you do it, i wanta pic please.
with all the DIY gear i've seen here, i'll have to do a centralised filter for all my aquariums and negociate a double decked growbed with CFL lamps in the bed room /fish room.
Not sure DW will appreciate the electricity bill!!
And i might go through the floor.

DDMan: have you thought of mesh/net cages in a rectangular concrete tank?
Would loose less room in the basement for sure.

Amacafish I was going to build rectangle tanks from concrete. However, I am now just going to use rubermaid stock tanks for the first 25% of my system so that I can get up and running. To finish the fish this year means I would need to have my system cycled and have fry already going. So I am going to focus on getting the nursery system made and an indoor system that I can run all year; the reason for this thread. I see no problem being able to get 1 fish a day to eat with this compact system. Janet has helped me get my math straight and I will be building this system in 3 weeks. Once it is done I will start getting ready to build the next 25% of my system. In all I hope to be producing 1440 fish per year; growing them out a full 12 months.

The only two questions remain. One, how much nitrogen will plants take up in a day. I need to determine how much grow bed area I need. Two, how am I going to heat and this system in the winter without natural gas or electricity input; I'm thinking wood gas stove.

The fluidized sand filter is very exciting to me because it is going to allow me to have a 52 inch 10 inch pipe instead of 3000 gallons of gravel. My back is already feeling better, LOL. To maintain the benefits of putting the solids directly into the grow bed I am going to prefilter the solids through the growbed. This way I can still grow fruiting plants.

Do you think it would be a valid test to take fish water in a Deep water Culture type setup and fill it with fish water then measure the nitrates before and after a 24 hour period?

What is the unit of measure for these test kits? All I know is my fish water is currently about 100+ on the nitrates.

To know the nitrogen value, i'd look at the NFT hydroponic recepies for lettuce, which are mainly water and nitrogen. They would give the nitrogen uptake by giving the quantities in the nutrients solution, and the duration of the solution.

Have you checked the maximum yield magazine on the net? I think that they have articles on the different plants and the fertiliser dosing in NPK and the daily dosage. Otherwise by finding the nitrgen dose in ash analysis. I'll check here if i can find soem details, if i do i'll post.

I'd go for a stove to heat the air of the basement, and an air heat exchanger with air extractors because otherwise the house will fall in bits with the rh, and you'll loose less heat then you would need less wood. Maybe adapt the air exchanger to the chimney and have the chimney piping going around the room with a slow slope.

Can't you do a solar heating system like Doug Basberg did, find his system in the members system if you haven't checked it out already.
Maybe plugging the pump to thermostat could let grab a few calories from the sun.

A few ideas that i hope will be usefull for you.

I found a paper by the university of Illinois that says Swiss chard can uptake up to 3.8 g/kg fresh weight in its leaves. http://www.siu.edu/orda/igc/proceedings/01/larson.pdf

Swiss Chard

For the calcualtions, you'll need the nitrate, nitrite and ammonia results to know exactly what were the parameters before and after.
Anyway i'd suppose to increase anyway the plant capacity from the calculations depending on the environemental factors you won't be able to control.

I think I will need to do experiments for all the common plants and chart the progress because absorption rates are going to change with the age of the plant. In the mean time I will start with 3 or 4 grow beds each about 6 feet in diameter.

Most of the aquarium test kits for nitrate are measuring the number of parts per million in the water. 100 is usually the high limit on ponds and I usually aim to keep mine under 40 in my aquariums.

That usually requires frequent water changes, which is what led me to look into aquaponics in the first place.

The gravel bed approach bundles all of your needed filtration methods: physical, biological (fish), biological (plant) into the one implementation of a bucket of gravel.

Unfortunately, while it can take care of all, it doesn't do them all equally well. This means that you have to size your components to the weakest piece. From what I can tell, that's the nitrate cycle for the fish.

When you separate those elements out a bit, you can make them each more efficient at the expense of a more complicated system.

If you use a FBF or a trickle filter for biological filtration and set up a dedicated physical filter, handle the aeration with a dedicated system, etc, then the growbeds are really only taking care of providing a place for the plants to grow and can be optimized for that purpose.

Whether that's a good thing or a bad thing to you will depend on your perspective. For smaller systems, it doesn't matter. For larger ones, the weighing of options can be more complicated.

It's a dilemma that appears in technology all of the time. Multi-tasking devices are nearly never as good at any one of their functions as dedicated devices are. However, they're usually good enough and are cheaper/easier to get than combining multiple dedicated devices.

That is an interesting though. I assume that the local pet store would sell reptile calci-sand?

I will get some and compare it to the fine sand blasting sand.