Backyard Aquaponics
A place to discuss aquaponics

Hi. I'm Geek2Nurse. That's because I used to be an engineer, and now I'm a nurse. Well, actually a nurse practitioner, but adding that on made the handle too long. As you might begin to guess from the diversity of my past occupations, I'm interested in a lot of different stuff. And right now, 'way up high on the list, there's an entry for aquaponics.

My husband and I just bought a house in a rural area of Washington, USA, and are settling down at long last. Which means that, at long last, I am going to have a greenhouse. And inside my greenhouse, I want to have an aquaponics system.

BullwinkelII (hi BullwinkelII! I tried to reply to your PM, but I'm not allowed) says I'm supposed to tell you all about it, so you can make sure I don't make any n00bie mistakes. And the truth is, I'd really prefer not to. So here goes:

What I have in mind, for starting out, is a 100 gal (378-ish liters) fish tank, for which I'll use a Rubbermaid stock tank I've already got on hand. That will be raised up a couple of feet off the floor of the greenhouse, because I want to use gravity as much as possible. I also have two 55 gal heavy-duty food-grade plastic barrels (I have those now, too, 'cause my awesome husband went and picked them up for me today -- they were previously used for soda concentrate) that I'll (actually my awesome husband will probably have to do it for me, since I have wimpy girl muscles and am lousy with a shovel) sink into the ground to act as the sump. I'll connect them together with whatever it is you call the upside-down U-shape of pipe that uses siphon action to keep the level the same in both barrels. I figure having the sump buried will help reduce the amount of heating I'll need to do in winter. The water will be pumped from the sump up into the tank, and then gravity-fed into the grow beds, where bell siphons (which will work perfectly, because they'll be made according to the detailed table BullwinkelII is going to create for varying pipe lengths and diameters) will drain them back into the sump.

I'm probably going to construct the grow beds from 2x12" lumber lined with pond liner. I think I calculated (it was during a staff meeting last week, and I left my notes at the office so I'm having to rely on memory here) that at 30-ish inches wide (the width the benches will be in the greenhouse) and 12" deep I would be able to have about 12 feet total length, probably split into two 6' grow beds. (Or is it better to have multiple smaller beds?)

I'm not sure what kind of fish I'll have...I've been wondering whether tilapia would work, or whether it would be too hard to keep them warm enough to breed here in Washington. My dad raises tilapia in Texas (in lakes, not aquaponic tanks), and I love how they taste.

Right now this is all kind of waiting for my greenhouse to get built. I've got most of the materials; it's going to be a 10' by 30' hoop and plastic greenhouse, with plywood ends. I'm working an extra locum tenens (temp) job to earn the money to get the rest of the supplies and get it put up so I can get started, so I haven't had a lot of spare time lately to do much more about it than just daydream. But that's a start!

I need to learn about pumps, and what size I'll need, and what to look for in a pump. And I'm wondering whether I could run it off solar-charged batteries, or whether I'll need to have electricity run from the house back to where the greenhouse will be. Which might be the better way to go, since I may need heat, too, and I don't know how reliable solar is through our grey winters.

I *think,* the way I've got it planned, the system would be okay for a while in the case of a pump failure. The fish tank would always be full no matter what, so there would be time to get things working again before anything started dying.

What have I missed?

Hello.

It sounds like a decent start to your new obsession

Good luck waiting for those tables

Generally speaking people recomend you turn over all the water in your fishtank every hour. Pumps are normally rated by the amount of water they can pump without pumping up at all. ie the volume per hours is at zero head. Most decent pumps have a (rough) guide as to what kind of flow you can expect at different heights you might want to pump to. Some have a nice (optimistic) chart showing the flow loss depending on the height you're pumping to.

So that, coupled with any plans for future expansion is generally what people use to choose their pump. ?If you're expanding grow beds, the same pump will probably work for a bigger system, but if you're adding fishtank, you might need more pump.

Another option for expansion is to simply add another pump. Even if they are both in the same system, for the slight loss in cost/flow, you get the extra security of having at least some water turnover in the case of a power outage or pump failure.

A lot of people add air delivered by an air pump and stone (the stone makes for lots of tiny bubbles) as additional oxygen if they are not pumping a lot of water, and some add it as a fail-safe. ie it's battery powered. And some just add it because fish like lots of dissolved oxygen.

A freshwater master test kit is also a really good idea to make sure you know what's going on with your water.

What media do you plan on using in your growbeds?

TWO pumps. That's brilliant! I was avoiding having two pumps in different places in the system, since things can get a tad complicated if they pump at different speeds, or if one fails and the other doesn't (the human body is a two-pump system, which is what got me thinking about this...it's a big problem for a lot of folks I see in the hospital). But two pumps in the SAME part of the system -- that's an excellent idea! I was going to have the water going into the fish tank fall from some height to add some bubbles (forgot to put in that part!), but maybe an air stone would add more? Or I could do both. Overkill seems like it couldn't hurt, in this instance.

Yeah, a test kit...thanks for the reminder.

Media: I haven't been brave enough to price the extruded clay media just yet. I'd like to use the real stuff, but failing that, probably the red lava rock they use for landscaping, as it seems like the next most lightweight choice. I saw something about testing it with vinegar to make sure it won't mess up the pH -- is that a reliable test?

There are other options such as expanded shale and expanded slate (stalite). Both of those should be pH neutral if properly processed and washed. You can contact web4deb on here about expanded shale. Stalite may be a bit harder to find as it is only produced in NC.

I found with media that the lighter it is the more expensive it is I opted into building a stronger grow bed and going with gravel, which would have been really inexpensive if I had a truck and could buy it by the ton. Along with expanded shale and LECA, growstones (made from recycled glass) are an option, though you have to do a special dance to balance the pH initially.

+1 on the gravel

Although the hands of the professional nurse side of you might want to put a layer of smooth stones on top of the rough gravel. Don't need to tear up your hands, and things grow just as well in gravel as they do in any other media.

Good to know. Although in the process of having background checks done for new positions the last few years, I've learned that apparently all the hand-washing has just about worn off my fingerprints. If I go with the gravel, it could finish them off once and for all. Might come in handy if I ever decide to give up on honest professions and turn to a life of crime.

That reminds me of a funny story. There was once a criminal who really removed his prints so he wouldn't get caught (instead of just wearing gloves). When he finally got arrested not having any prints was just as incriminating as if they had found his prints everywhere and he went to jail.

Hi geek2nurse, my native land is Washington. I was going over your plans, and the thing that struck me was: not enough water. I would recommend upgrading the fish and sump tanks to a larger size for better temperature stability. I remember many a frosty mornings, and added water volume would help offset that. Your greenhouse helps, but if you are building a greenhouse to house an aquaponic system, why go small? Regarding siphons, have you looked at the Affnan style siphons? They are quite problem free.

Hmmm. I guess I was going small so I could hopefully keep any failures to a somewhat less than spectacular level. Dang. The only parts I've GOT so far are the tank and sump! I did see a 275 gal IBC tote on Craigslist today, but buying it would push my greenhouse build that much farther out. (Saving pennies to make it all happen, and waiting is HARD! I'm really bad at waiting...*sigh*) I *was* thinking that eventually I might add a second 100-gal tank...the greenhouse will be 10x30', and 200 gallons of tank plus the 24 feet of accompanying grow bed at the width of the benches I'm planning would fit nicely down one half of the greenhouse, leaving the other side for regular greenhouse stuff. Maybe I *should* see about getting the IBC tote...



I haven't, but I will now!

Smaller volumes of water change faster. That is with ammonia levels, temperature, ph. And faster changes are harder on fish. Keeping it small would be to start out with fewer fingerlings. Speaking of fish, I am not sure about the legality of tilapia in Washington. But the heating costs would probibly keep them cost prohibitive anyway. Trout would probably be a better choice through the winter. People also like catfish, but I can not have them in Cali, and again I do not know the law in Washington. Silver perch can handle a wide range of temps too.

Good point. And I suppose I could sell the tank I have, to help finance a larger one. I guess I need to rethink the sump, too. I wanted to make the sump roughly the same volume as the grow beds, which would be roughly the same volume as the tank, if I've got my mind wrapped around that stuff correctly. I'm kind of hooked on the idea of a series of barrels for the sump, because they have tops to keep out dirt, debris, and small children. And smaller individual volumes hooked together seems okay for a buried sump, since the temperature will be buffered by the soil. Are my thoughts on this part making sense so far?


Mmmmm, catfish! I like perch, too. Actually, I don't think I've ever met a freshwater fish I didn't like.

Here's a photo of my greenhouse, in its current incarnation. I'm excited, because I just discovered that my first locums tenens (apparently that's how you say "temp agency" in Latin) paycheck deposited today along with the one from my regular job, which means I can make our first house payment and still be able to buy the rest of the greenhouse materials I need!



This is the site for the greenhouse. The former owners had a garden here, about 20x30'. It's covered with ground cloth right now, because they didn't plant this year, and in this part of the country, exposed soil doesn't stay that way long. The greenhouse will go lengthwise along the half that's closest to the camera. The back half, where my granddaughter is playing on top of the 100 gal stock tank I *was* planning to use as my fish tank, will be for an outdoor garden in the summer. Unless I outgrow my greenhouse and decide to put in a second one.



If it's still available, I'm going to go look at a 275-gal IBC tomorrow and think about making it my fish tank instead. Anybody want to buy a 100 gal Rubbermaid stock tank?

I made myself a spreadsheet so I don't have to keep recalculating by hand when I change my mind about things. And also so I can visualize sizes when reading non-US posts, since I don't naturally think in liters and kg (except down in the smaller numbers, like how much soda to buy when my kids are all coming over for dinner).

My spreadsheet tells me that I can use a 275 gal (1041L) IBC with 36" wide grow beds (12" deep) to achieve a 2:1 ratio (total grow bed volume to fish tank volume) and fit everything down one side of my 30' greenhouse. (That leaves the other half for other stuff...or for a future second AP setup? ) It also estimates that I can expect to keep maybe 20-25 fish in such a system, although those numbers are kind of rough still, since I don't know how big to expect my fish to get, partly because I don't even know yet what kind of fish I'll have. But it's a start.

My husband says I'd better stay enthused with aquaponics for a long, long time if he's gonna do that much digging for me.

Cool idea on the spreadsheet. From the sounds of things, enthusiasm is in plentiful supply. I think he will have a hard time holding you back.