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azawacki
08-17-2011, 12:09 PM
I'm new to aquaponics and have been researching extensively for the last month or so. I am interested in building an indoor system for the basement initially.

I've read a number of things, from ft:gb ratios and whatnot. As I get close to actually building my system, a number of questions arise:

1. I am initially starting with a 75gal tank, but I'll only put in 40gal of water at first. If I'm using gravel, using a 1:2 ratio, this would imply I need something like 11 cu ft of gravel in my grow beds, or roughtly 1100lbs (550lbs per growbed). More if I fill the fish tank. Is this correct?

2. Just for space considerations, I am planning on stacking my entire system, so it looks something like this pictures which are not yet finished. It currently shows a single tier for the grow beds, but I'm planning on a second tier above the first. All in, it seems like using gravel adds up 3/4ths of a ton of material. (The fish tank should come in at around 450lbs with 40gal of water.) Is this something I can make out of wood and have it sturdy?!? Note that in these pictures, the base is made from 2x2s, all of the plywood is 1/2" and the growbed supports are 2x8s.

http://www.jzdocs.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=1750&g2_serialNumber=1
http://www.jzdocs.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=1755&g2_serialNumber=2

3. If I use hydroton instead of gravel, it looks like around 300 liters of material (6 50l bags) which adds up to about 250lbs, or 125lbs per growbed. Does the weight of the gravel make hydroton the only choice? Price difference is about $75 for gravel at the local store vs. $260 to have the hydroton shipped to my house.

4. Is a 5 degree slope on the growbed the right slope to ensure proper drainage?

urbanfarmer
08-17-2011, 12:21 PM
1) Yes.

2) I held up over 2 tons of water with just 2x4's and some blocks. I'm no architect, but there should be some kind of design with "wood" that will do the trick. Maybe you have a carpenter friend?

3) Hydroton is lighter and has more surface area than gravel, but it's more expensive.

4) I would make it perfectly level. You don't need a slope whatsoever. It's not a bathtub! :-)

Bioritize
08-17-2011, 12:48 PM
I agree with UF,

After I built my 40 gal setup I instantly wanted more water. I would build 150 gallon FT, if I were to do it like that. That way you can grow out about 1 lb of fish for every 3 gallons of water or 50 lbs of fish and if your little guys get to be 1.5 lbs you can have about 33 fish give or take a few.

Is this indoor or outdoor?
If it is indoor, what are you going to do for light? I would make the grow beds side by side if your indoor to be able to use the same light.

azawacki
08-17-2011, 01:31 PM
My current plan is to stack a second growbed about half way up the post from the previous growbed. Then I'll cap the top of the shelf. I am planning on attaching grow lights under the second bed and to the top of the shelf. The space behind the fishtank is intended for things like a UPS and wiring infrastructure. I'm not certain yet on all of my math, but I think the two growbeds (about 2' x 4' x 6") will support about 40 gallons of water. Once I'm happy with the way everything is working, I'd build a second shelf to set next to this one wihtout a fishtank in the bottom, and have a second set of growbeds, which should allow me to fill up the fish tank. It should support about 25lbs of fish I believe. I'm currently in the design stage, and am going to finish my google sketchup including the lights. I have the fishtank already, but I've not yet figured out what fish to use and what is easily accessible in northern Virginia.

This is an indoor system. I'm currently planning on putting it in the basement near the drain for the air handler, which will handle small spills (nothing major) without having to worry about anything. The floor is cement. My concern with an outdoor system is that a green house (pretty much any outdoor structure is a hassle due to HOA involvement) is not feasible in the area that I live, so nothing would grow in the winter, and I'd have to restart the system every year from scratch in the spring. With astounding success, I'd probably expand into the garage next. :)

davidstcldfl
08-17-2011, 03:57 PM
Hi azawacki, I've heard of guys getting dicounts for hydrtron at local hydroponic stores, when they go in and talk about growing 'veggies' in aquaponics.
I'm guessing because they figure your not raisng 'cash' crops.... :lol:

It might be worth the try :)

urbanfarmer
08-17-2011, 05:10 PM
Hi azawacki, I've heard of guys getting dicounts for hydrtron at local hydroponic stores, when they go in and talk about growing 'veggies' in aquaponics.
I'm guessing because they figure your not raisng 'cash' crops.... :lol:

It might be worth the try :)
HM, WORTH A TRY MY FRIEND!!!!

Last time I was at the hydro shop we couldn't stop laughing and making jokes because the clientele was obviously not raising tomatoes!!! :lol:

badflash
08-19-2011, 01:55 PM
Make sure there is enough head room in the tank so that you can net the fish and see them.

The volume of the gravel isn't the critical part. What is important is the surface area. 10"-12" is enough depth. The general rule I use to to figure out the surface area of your water as if it were a cube. You need 2X that much surface area to grow enough plants. For 75 gallons you end up with 10 cubic feet. That means you need about 4.3 square feed of grow bed. This isn't and exact science, so a little bigger is better.

Madmax478
08-20-2011, 02:04 AM
How many fish are you wanting this system to support?

azawacki
08-20-2011, 08:58 AM
Honestly, I haven't thought the fish through yet, as I haven't been able to figure out what fish I want yet. Tilapia is popular, and since it's indoor it should be good for the temperature, but I'm having difficulty finding a local source of fish in my area. I'm going by a few guidelines:

1. 1" per gallon
2. 2lbs per cubic foot
3. 3lbs per gallon of growbeds

I've even considered going to a local lake to catch some sunfish, as they are in the 2-3" range and are easy to catch, though I haven't yet checked the legality of that in Virginia yet. Tilapia requires a couple of forms to be filled out, and then you can have them... So I've not figured this part out yet. I'm planning on 40 gallons of water, and I'm not 100% certain how to calculate my growbed gallons, but if it's straight off the dimensions of the bed area, then I have about 80 gallons of growbed (4'x2'x.5')x2.

Anthony

Oliver
08-20-2011, 11:57 AM
The amount of total water in your system is not as important as the amount of total gravel to the fish poundage ratio. You will want at least 5 gallons of bio-filter gravel (less for Hydroton) for every pound of fish (fully grown weight) you plan to have in your system. Hydroton displaces about 50% of your water in the grow bed, but once it is saturated it has the same density as water for weight calculations. The inch of Hydroton above the water line weighs less than water. Gravel, on the other hand, displaces more water, perhaps 2/3, and has a higher density than water; so your weight estimates are probably correct.

Make sure that your fish tank gets good light. You will need to cover your fish tank with something (preferably a net) to keep your fish from jumping out.

Go ahead and put as much water in your fish tank as you plan on having when the fish are fully grown. That way when your grow beds all fill, the water level in the fish tank won't be too low. The more water in your system the more stable it will be both thermally and biologically. With more water (and less fish density) your chemistry changes slower and gives you more time to correct it, if required.

Oversize your water pump and put control valves on your grow beds so you can individually set their fill rates. The fish solids will accumulate in the vertical water lines feeding your grow beds so you will need to purge them every few days by fully opening the valves to the grow beds beginning with the lowest bed until the water clears and then resetting it to its previous siphon cycling position. Then go to the next higher grow bed and do the same. You may find that you need to alternate this purging between grow beds as most of the solids may only be in the lower part of the vertical pipe. That way, your grow beds will each receive some fish waste solids and allow them to break down over time.

In oversizing your pump, make sure that you have enough volume to exchange the water in your fish tank twice an hour at twice the highest required head pressure (highest grow bed). Take this extra pumping power and jet-back some of the water from the pump into your fish tank for added aeration. It would be best to take the jet-back water from the highest point in your grow bed fill line. That way, you will have a greater flow up through the line filling your grow beds; and either the solids will move up into the beds, or the water flowing back down to your jet-back will have less solids in it (thereby keeping the jet cleaner), or both. The jet should be removable for easy cleaning.

Water pumps are much more effecient than are air pumps, so this is a good way to add air to your fish tank water with minimal electricity use. You will need some additional aeration in your fish tank. Also, with the added pump pressure, you will find that the grow bed control valves will not become clogged up with fish solids, as they will be pushed through the opening. Use ball valves throughout your system, as they remain where you set them. Remember, no metal in your water circulation or elsewhere in the system.

Your system looks well thought out and I believe you will be successful in getting it to work. Obviously, you will have limited vegetable grow height so you may be limited to green leafys, which is all you will want to grow until your system matures.

Oliver