Where is the advise coming from?

[TCLynx]

I have lately read some things that give very cut and dried black and white answers about that is necessary for Aquaponics. This really bothered me because it didn't necessarily make note of the other parameters that affected such answers. There might be some advise you shouldn't second guess (like when you ask for help and explain the trouble, then it is usually prudent to listen to the help given) but when very hard fast narrow rules are handed out as if they apply equally to all situations, I have already learned by trial and error that many of those rules may not apply to all situations.

It is really important to know a little about where advise is coming from. This can be especially true about gardening and farming. Aquaponics, even more so.

For instance, some one might say that you must have a temperature of 74 degrees F to do aquaponics. Well, I know that my set up rarely has that exact temperature for either the air or the water. That bit of advise comes from some one with experience in climate controlled greenhouse aquaponics growing tilapia and mostly salad greens.

Or some one else might write that if the water isn't chlorinated coming out of the pipe, then you should treat it as agricultural water and chlorinate it yourself and air it in a holding tank before putting it in the system. Well that might be true in a place where wells are not good (due to salt intrusion or too deep a water table) but in my location, I've got a good well and therefore don't have to worry about chlorinating my water or using city water. Also, that advise came from a place where they are not yet using chloramine. See Chlorine only takes a few days of heavy aeration and flowing around under the sun to be well cleared from a system, Chloramine takes weeks.

And here is a very important one. If some one tells you that ammonia or nitrite levels up to 5 or 6ppm (or even higher) are safe for fish, they are probably talking about tilapia!!!! What can be done with tilapia is not a good indicator of what other types of fish can handle. Most other types of fish are far more sensitive to poor water quality and will often suffer if subjected to much more than trace nitrite levels for too long. Ammonia level toxicity will be affected by pH and temperature but still I don't like to let either ammonia or nitrite get over 1ppm with my catfish in the systems and I will usually adjust feed or filtration rates when I see anything .25 ppm or up.

Similar goes for dissolved oxygen. Tilapia may survive dissolved oxygen levels below 4 mg/l but most other aquaculture species need 4 mg/l as their minimum!!!!!! And most all fish will grow and eat best when dissolved oxygen levels are near max or saturation for whatever the water temperature is. (Warmer water can hold less oxygen and salted water also holds less oxygen.)

So, when reading advice about Aquaponics, it is good to also find out where the advice is coming from. Not simply the country/state or climate the adviser is in but also the type of aquaponics they have experience in and the type of fish they grow.

Also important would be what sort of operation, commercial that has daily attention from staff with a checklist of things to check and clean daily, or backyard where it might go for a weekend or week with no one looking in because they are on holiday.

Maintenance, I call my system low maintenance because when I go away, I literally only expect the neighbor to walk past and notice that the pump is running. A commercial system operator might call a raft system low maintenance because they can lift the rafts out to a comfortable work station for the workers to do the harvest and re-planting daily/weekly because that is better than them having to bend over gravel beds to harvest and re-plant daily/weekly. It isn't that big a deal to walk out and pick a few plants for dinner from a backyard system even if one needed to bend a little to do it and most of us don't harvest an entire gravel bed and re-plant on a daily or even weekly basis. We pull a plant we want and occasionally sprinkle some seeds or push a few bigger ones down into the gravel, that doesn't usually break one's back even if the beds were on the ground. So, both methods are low maintenance for their particular function but a raft system might not be so low maintenance for a backyard system (since it usually requires separate facilities to start the seeds and then planting them in net pots and so on) and the media bed system is not so good for a fast salad/herb crop type commercial system.

The devil is in the details as they say. Learn the details to know how some one's advice might apply or perhaps not apply so much to your specific situation.

[TCLynx]

ernie,
My systems so far have simply been backyard systems, this is why I haven't been concentrating on the whole ROI and trying to grow out a huge crops of fish for harvest at a particular size in a season and all the other things that go with commercial production.

My comments about adjusting feed were really more along the lines of when cycling up a new system (because I did that again not too long ago.)
I agree that ammonia and nitrite should be 0.

Again, I'm not investing thousands of dollars on DO meters and testing 8 times a day because I'm not running a commercial system. I'm running a backyard garden that happens to produce lots of fish. I'm not even home to do such testing for periods of time. If I were running a commercial system, you can bet I would probably have DO meters installed that could monitor DO and track it constantly and chart it on a computer. But some of those DO meters cost almost as much as my complete 300 gallon system. My big system cost more but that one grew as I learned so It paid for my education.

My experience is primarily in Flood and drain backyard scale media systems. I like extra deep grow beds. I've experimented with some NFT and some Zipgrow towers. My location is Sub-tropical central Florida. It gets too cold here in winter for tilapia but I've found Channel Catfish do well year round and get nice and big and we like the taste better. I sell Aquaponics Indexing valves here in the USA and I've been testing out the use of them with lower power pumps to see what will work.

[TCLynx]

Salinity can be tested in a couple of ways. They do make test kits where you can use test tubes and droppers.
You can also get a hygrometer with is probably most appropriate but get one that is designed to measure the range you need. I have sort of used a TDS meter but it is only really easily useful for very very low levels of salinity.

[David Hart]

Friendly's newsletter 19, has some good info on DO testing.....
http://sn138w.snt138.mail.live.com/default.aspx?n=884133395&wa=...

[TCLynx]

I have only rarely tested my DO in my systems. I have extra aeration going in all fish tanks and there are pumps running constantly providing extra flow and aeration.

I only got the test kit and used it a few times out of curiosity.

[Raychel A Watkins]

You are so right TC. I have noticed that there are people who tell you that aquaponics only work one way. I find that the only thing similar needs to be that the water goes from the fish to the plants back to the fish. The great thing I have found is many ways to do the same thing. I love the experimenting. I started with rafts because that was the way I learned. I have since started to try gravel beds because I like what I see. I love Nate's towers and hope to add some some day.
this web site has shown me more ways to do lots of things. I have 2 WOOFers at my house now. They are from France and Canada Mat is a cival engineer. He knew nothing about aquaponics when he came. But now he and his girlfriend know a lot and they have taught me a ton of things. I have really been blessed by them. We should all be like students and listen to what people have to say. Meditate about the things and then if we want to experiment and see if they really do work. Again I say this site is wonderful for its sharing and not try to tell people that it must be done a certain way. Keep up the sharing I learn a lot

[Harold Sukhbir]

Just do all of us one favor....... never stop talking because i never want to stop learning.The ones with experience provide the balance in this maze of "advice". Thanks.

[TCLynx]

There are a few different ways to test dissolved oxygen. I've got one of those little test kits where you get the water in the tube and immediately add drops of one thing then drops of another then invert the tube then add more drops and compare to a chart. Basically, a Test kit. Not too costly but not the easiest or most accurate way to do it either.

They also make test meters that are probably worth the investment if going commercial or raising very $$$$ fish or you just really like that sort of thing and have access to meters and equipment without breaking the bank so to speak.

I think you can even get dissolved oxygen probes that work with the really fancy computer controlled aquarium controllers and such but I've never tried any of that stuff.

Similar answer goes for pH. I usually just test pH several times a week for my one system and perhaps a couple times a month for my heavily buffered system. Again, I've been using the test kit with tubes and droppers but many people use meters.

Drawbacks to meters, the initial cost, the calibration and storage solutions and replacing the probes and batteries.

Drawbacks to test kits. Takes a bit longer to run the tests and you have to trust your eyes to compare the tube to the color card. And then of course you have to buy new when you run out or if you stock piled, they can go bad if kept on the shelf too long.

Most people doing Backyard scale aquaponics do just fine with a thermometer and a freshwater master test kit. You can add a dissolved oxygen test kit for probably between $7 and $20.

[Sylvia Bernstein]

Well said, TC, as usual. I think that the answer to most questions in aqauponics should start with "it depends" and go from there. It usually depends on whether you are looking at going commercial or backyard. It depends on the type of system you have, or are planning, and the type of fish you are growing. It depends on the climate in your environment and the amount of space you have. It depends on your water source and perhaps on the reliability of your electrical source. It depends on how often you travel, and how much you are willing to fuss with things. Thanks for pointing this out!