Backyard Aquaponics
A place to discuss aquaponics

Hello everyone, I'm new to the board and the general concept of aquaponics. Have started researching it and am completely enthralled and totally hooked (or neurotic as my husband would say) already. I have been scrolling through old posts a lot!

Long story short I currently live in Malaysia but hope to be back in Texas (Houston area) by next summer, and fully intend to have a go at aquaponics when I get back! As a relatively new stay at home mom, I think it would be perfect to keep me occupied and produce healthy food in the process. In the mean time I am trying to do as much research as I can.

I have a few questions I was hoping to get some feedback on. By the way, the info on this board is 100X better than any book or report I've come across. Thanks to all of you with experience that take the time to share it and your knowledge!

So questions:

Can freshwater prawns and/or louisiana crawfish (not in the same tank) support an ap system w/out fish? Not just leafy plants, but tomatos etc. Would love to try red claw, but apparently are illegal in Texas.

If I do need the fish, could I go with native fish like bass or perch? There are a couple ponds and a creek on my place, so I could trap all I would need. Would definitely prefer to start that way in case I accidently kill 'em off.

Would it be ok to introduce water from the pond to help kick start the system, or would it be taking a chance at introducing disease?

My land has well water with a lot of iron in it. I have read that heavy metals can be harmful to crawfish. I'm sure it's good for the plants, but would the iron in the water be a problem?

I'm sure I'll have a million more questions, but that's it for now. Thanks in advance for any input you guys may have.

Hay and welcome!!!!

I'm not sure if a crayfish system would produce much veggies, it is all a balance, It might take a lot of crays to support a tomato plant and crays need a fair bit of space and they are escape artists.

Yes you can use native fish. You may not need to try trapping wild fish though. You can probably (for far cheaper than you might expect) get some farm grown fingerlings near home. (I get channel catfish fingerlings for as little as 30 cents each.)
Anyway, blue gill, bass and channel catfish are native fish that can be grown in AP and can be gotten as fingerlings from fish farms.

There is some risk from using pond or river water, you will have to decided if it is worth the risk to use it. When you say introduce water from the pond, do you mean an ornamental pond you have or is this a wild pond? If an ornamental pond, I'd just wash the pond filter into your grow beds once you have them half filled with gravel. The start fishless cycling which is usually quicker than cycling with fish. Some worm castings along with the worms can help too.

The well water with lots of Iron in it will actually probably be a good thing for AP since it will probably mean you don't need to add iron supplements to your system. Just make sure you don't use limestone as your gravel since it would keep the pH too high for the plants to take up the Iron.

Thanks for the response TCLynx.

In theory could you have a larger FT to GB ratio, or would that be too much water to try to cycle? Space won't be an issue. We have 70 acres. Much more interested in crawfish and shrimp for food. Not a huge fish eater. On the other hand, I feed my dogs a fish and raw meat diet, I guess they could eat the fish!

I'm pretty sure catfish would compete with crawfish or shrimp, guess could just do two tanks. I know perch and bass will eat crawfish, but could figure out a way to separate them in one tank.

Yes, I was referring to a wild pond. Would worm castings have enough nutrients to support the plants if I started with a fishless cycle? What about cattle or chicken manure? Have access to all I want (my Mom's place is full of crap). Would it affect the water quality too badly? Dont want to use chemicals because I would def. like to have some sort of fish later, just a little worried about killing them while getting the cycling sorted.

Good to know about the iron, I was afraid I would be fighting an uphill battle from the start. I will probably use pea gravel or river rock for the GBs.

I would not use manure from warm blooded animals since that can introduce e. coli and salmonella into the system.

To fishless cycle, you need an ammonia source which will also provide nitrogen for the plants once the bacteria colonies start converting it to nitrates. The ammonia can be in the form of pure ammonia like you might use for cleaning but you need to make sure there are no fragrances, detergents, soaps or other additives that could be bad for fish and bacteria, this is sometimes very hard to find. Another source would be urea fertilizer balls, be ware that these take a fair amount of time to be converted to ammonia before the bacteria can get to work on them converting to nitrite then to nitrate. And the cheapest method I know, Hummonia (Pee, urine.) Fresh urine also takes a little while to convert to ammonia but at least the enzymes involved are already included in the urine.

There are a few notes about cycling with hummonia. 1, if you leave it bottled for a few weeks before using it, the urea will have already been converted to ammonia so you don't have the lag time on the ammonia readings as with fresh or urea fertilizer. Also the act of keeping the urine bottled for a few weeks also has the effect of killing off things like e. coli that is often on and in the human body and therefor can get into urine in small amounts. As the urea converts to ammonia, the pH of urine goes up and the ammonia and the pH kill e. coli. On the pathogen front, it is probably best not to use the urine of a very sick individual in an AP system, (I'm talking illnesses like Typhus, cholera, etc) or people taking strong medications that tend to come out in the urine like Chemo therapy. Now if you are on antibiotics, you might not want to be peeing in the system for the duration of the medication since antibiotics come out in urine and they would be bad for the bacteria colony you are trying to grow.

Anyway, I ran a system pee-ponic for quite a while till I needed the space for my fish. I still needed to add about the same supplements as I did for regular aquaponics. Potassium and trace minerals are often added using Maxi-crop original 0.1-0-1 (seaweed extract) and iron (though you probably won't need so much iron.)

As to growing the shrimp and crawfish, they need lots of space just for themselves. Special requirements for crawfish is a way to keep them from escaping since they are escape artists. I've heard of people growing prawns or shrimp in DWC beds under the floating rafts.

As to what to do with extra fish, well I've been feeding small tilapia to my chickens sometimes. They like the ones that are only a little bigger than pumpkin seeds best. I'm sure you dogs would love some fish. You probably want to keep the crawfish, shrimp and regular fish separate. I've heard that bluegill can become quite aggressive to bass in tank culture while in pond culture the bass are the predators. I would guess that bluegill or catfish might be your best fish choices. I wasn't that big on eating fish before but now I'm getting better at it.

Thanks again for the advice.

Hmmm..."hummonia"...have to say, it never would have occurred to me.

I'm not sure I quite understand what you are trying to ask here. Are you talking about having lots more grow bed than fish tank? Or lots more fish tank than grow bed?

If you want to stock lots of fish for the size of a fish tank, you can easily need twice as much grow bed as you have fish tank to take care of the filtering. You can only support as much fish as you have filtration for them. When you start getting extreme on the amount of grow beds in relation to the fish tank, you need to deal with how to flood and drain the grow beds without running the fish tank dry. And then there is the question of enough nutrients to keep the plants going.

Aquaponics is all about balance.

I meant, in order to have enough prawns or crawfish to support the growbeds, could I have a larger fish tank (to accomodate a larger number of animals) to support the grow beds, and would the grow beds provide enough filtration to support the larger tank?

aaah,,,

I am afraid that you need the amount of growbeds to suuport the amount of water you have, regardless of stocking density. Within reason.

4000 litres of water requires as a bare minimum 2000 litrres of growing media. This applies wehter you have 20 fish or 400 fish. You gotta have the filtration for the water volume, not the fish amount.

Well I kind agree but there are ways around it too. Though the ways around will add to the complexity. You can use other forms of filtration instead of flood and drain gravel beds. Something like a swimming pool sand filter can help to filter the water without having to take up as much space as a grow bed. Also something like a pond skimmer/upwelling waterfall filter can greatly help a system. I know that most ornamental ponds do not have as much filtration as aquaponics does but they usually have far more flow for the amount of filter they have.

I think the biggest challenge with Aquaponics and balancing the circulation and filtration is that gravel beds with plants, don't really need to be flooded as often to keep the plants happy but for filtration having constant flood and drain cycles will filter more water. Also, you can only circulate so much water through a gravel bed per hour so that you be part of why one needs so much gravel to support a given amount of fish tank.

I think it is actually more about circulating enough of the water through some sort of filter each hour. For most AP systems we recommend pumping the equivalent of the tank volume each hour. This can get tricky when talking about swimming pool systems. This has a lot to do with aeration as well as filtering. Stagnant zones of water or "dead" zones can be really bad in tanks that don't have enough circulation and aeration.

To some extent, I'm rambling here and don't have much in the way of hard fact or experience to back some of this up.

Ok, so...fish it is.

I notice in a lot of the Aussie systems, they have crayfish or yabbies in the sump. The sump collects the filtered water, which is in turn pumped to the fish, correct? Does having the yabbies in the sump not affect the water quality before being pumped back to the fish tank?

Can you explain the actual purpose of the sump?

I don't think koi or goldfish eat shrimp or crawfish so you could polyculture them in the same tank. And just keep the fish as ornamentals, and koi and goldies can handle summer and winter temps.