Introducing Fish Into a New Aquaponic System It’s time for a little Q&A with Dr. Nate Storey of Bright Agrotech (http://brightagrotech.com/)
Question #1: How long do I have to wait before introducing fish into a new aquaponic system?
Answer #1: On every new system you have to wait until you are cycled and that’s usually about six weeks or so, on average.
In colder climates it takes as much as eight or ten weeks. Some folks in warmer climates can cycle in four weeks. It just really depends on the media that you are using, so whether or not your media has really high biological surface area and whether or not you are using something to inoculate your system. So when starting system it always helps to start with live water. That’s water that already has the live nitrifying bacteria in it. You can find a healthy aquaponic system or even a healthy aquarium. Some folks will use stream water or pond water. And all of these things are really good systems with inoculated water you can get your system started with.
Now the caveat, if you do use kind of an inoculants like that you want to make sure that it is coming from a healthy body of water or a healthy system because if it is coming from a system with diseased fish then you can run the risk of introducing disease. So if you are inoculating you can start it a lot sooner. You can put your fish in as soon as the system is cycled.
Question #2: “What are the pH limits for fish, more specifically Tilapia? My water has 7.3 pH and it’s out of the ground.”
Answer #2: As far as pH limits it really depends on the fish, but people tend to over concern themselves about pH values and their fish. The reality is that fish are pretty tolerant of a broad range of pH values. Tilapia tend to like more alkaline conditions. So they like basic water. For the most part they have historically adapted to African lakes and the pH values in those lakes are often up in about eight, eight in a half. Actually, they have been found in water considerably more alkaline than that, so they are more adapted to alkaline waters. The one thing we have found is they don’t like breeding as much with the lower pH’s. Occasionally, we will have to bump the pH’s up to around seven to get our tilapia to breed but beyond that the tilapia will handle anything from the high fives all the way up to nine no problem. In that regard I would not worry too much about getting your pH to a specific level based solely on your fish. They [tilapia] are going to tolerate just about any pH range you can throw at them. Your 7.3 pH is pretty average in most aquaponic systems and your fish will be just fine in that range. You can actually drive it down closer to six over time and your tilapia are going to tolerate it just fine. For more related information, Visit verticalfoodblog.com