I'm working on setting up a small system - my first system - in my English basement. So far all I have is a 55 gallon aquarium. I'm getting excited about getting it up and running so I'm making it a goal to have all the supplies and get it set up within a month. However, before I make any of my next purchases, I have some questions. First I'll give you some specs:
I'm setting it up in a little nook 56" wide; ceilings are 81" high
aquarium size: 48.5" x 13" x 21"h
The aquarium will sit on a desk: 46" x 20" x 30"h
My initial plan was to set the grow bed directly on the aquarium or make a stand for it so that it would hover directly above it. Now for my questions:
1) Grow bed size: Does 8 or 9 cubic ft make sense?
2) Grow bed container: there are luckily a couple hydroponic stores near me here in DC, but the grow beds they sell seem pretty expensive for what they are - $50-$80 for 2x2 to 2x4 sizes. Are there cheaper options? I checked Home Depot today and I wasn't able to find any containers that looked like they could be transformed into grow beds.
3) Since I'm making this in my living room, I'm trying to make it somewhat pretty, so I thought about making a custom grow bed out of plexiglass and nontoxic sealant. Has anyone tried this? Is it feasible or ridiculous? I'm tempted to just scrap the idea because I really don't want to have to deal with the mess that would result from a construction that couldn't take the pressure.
4) Plumbing: I was originally planning on making a bell siphon, mostly because that was the only method I knew about, but I've since learned about others: looped auto-siphon, flush, and a combo of a timing and draining straight out of the bottom. The looped siphon seems the most appealing now. Any reason to use one method over another? I happened to see Sylvia's article in Urban Garden today (http://urbangardenmagazine.com/2010/11/aquaponics-explained-%E2%80%...) and was wondering if there was a reason she didn't mention the looped siphon.
5) Pump: what size do I need? The smallest one I saw at the hydroponic store here is 40 gal/hr (http://www.capcityhydro.com/product_info.php?cPath=1&products_i...), but I'm curious if this could handle the effluent from the aquarium or if it's strictly for hydo use.
All input and criticism welcomed and appreciated! Thanks!
1. You want about 55 gallons of grow bed to start with. Try and get beds that are 300mm or 30cm deep. This is the optimal depth for plant health.
2. Check online for used or new food safe bins. My first system used 5G buckets, even know they were a little to tall. Many fast food restaurants give away pickle buckets
3. Plexiglas is probably the most expensive way to go. But it would look wicked if done right.
4. A looped siphon is the cheapest siphon to make. But IMO a bell siphon is easier to clean in case of problems.
5. You want a pump to be able to move your fish tank water around a bit (100-200 gph) then enough to fill up your grow beds every 10-15 mins (~300 GPH on 55 gallons). The higher you need to pump upwards the more GPH you will need. So around 300-400 GPH should work, again depending on height.
1. Does that mean the volume of the grow bed should be the same as the tank, meaning it would hold 55 gal if there was no media?
5. If I had a 200 gph pump, does it literally pump 200 gallons per hour or does that depend on how high the water has to travel? My goal is for the pump to carry the water about 35"-40", but I can't say that definitely as I'm not sure what kind of grow bed I'll find. Is it generally pretty easy to match the siphon rate with the pump rate? If I used a bell siphon or looped siphon, should I also use a timer?
1.Exactly. In a properly tuned system you can have up to 3 times the volume of growbed to fish tank volume. But you would need your tank absolutely packed with fish. A good starting or home ratio is 1:1.
5. You are describing a phenomenon called "head loss" most pumps include a head loss chart to tell you how many GPH you will get at a certain height. Elbows, T's, and pipe bends all give varied amounts of head loss as well.
6. You do not want to match the flow rates exactly. You want your beds to drain faster then they fill up or else if you match your pumping rate exactly to the siphon rate your beds will never flood.
7. A siphon is used generally to replace a timer. It normally is easier on the pump to keep running then to constantly shut on and off.
Since this is going to be a system in restricted space you might also want to think about running constant flood at least for the initial cycle up. The easiest ways to switch between flood and drain and constant flood would be to 1, do bell siphons and to make the switch simply pull the bell out so the water will simply use the stand pipe as an overflow. Or in a timed system simply pull the timer out and let the pump run constantly.
12 inches deep or 30 cm deep is the "standard" minimum depth recommended for aquaponics but there are systems out there running smaller beds. Shallower beds can be more challenging to get a good flood and drain going and I would be more likely to use them for constant flood for plants that like more water (like water cress, water chestnuts, and some others.) I'm using some $12 mortar tubs from Lowes for my water chestnuts and they are only like 7" deep.
If you really want pretty, you might get one or two of Sylvia's grow beds and add a sump tank under the desk.
I'm trying to do this in the most effective way possible, so I may journey out to Home Depot and see what I can find there. Maybe down the road I'll upgrade to something a little prettier.
Some of the systems I'm seeing on the internet have another tank that sits above the grow bed. What purpose does this serve?
I recommend having at least as much volume of grow bed as you have fish tank volume so yes go with two of those bins. And then you want to look for a pump curve or chart with the pump that will tell you how much water the pump will move at your desired height. Make sure to go a little larger than you think you need to make up for friction in the pipe fittings and bio-slime build up over time. So if your fish tank is 55 gallons you need to move at least 55 gallons per hour at the very minimum. I would probably recommend looking for a pump that will move at least 100 gallons per hour at your desired height if you will be running the pump constantly. If you will be doing timed flood and drain you will need your pump to move that amount of water in the amount of time the pump would be on each hour.
This pump might do it for you but it may be almost too small as it gets gunked up.
Here is another pump that would do and would be big enough to expand in the future
The model QP13 should be good for up to a 100 gallon or maybe even bigger fish tank even for timed flood and drain.
If doing timed flood and drain you will probably need to add an air pump and air stones into your fish tank. Even in constant pumping with spray bar aeration it may be necessary to add supplemental aeration when the water temperatures get too high or fish load is too heavy.