If you use the full editor and click on notify me when a reply is posted you will be emailed
Good eye rfeiller...
"Freedom is never more than one generation away from extinction. We didn't pass it to our children in the bloodstream. It must be fought for, protected, and handed on for them to do the same." - President Ronald Reagan
Please see badflash's link to the "Tank Culture of Tilapia" published my SRAC. You can't go wrong with that as your guide.
This information is straight from the publication; although, I cannot agree the stated nitrate concentration figures as toxic based on my research and experience. There are ample publications and research that state nitrate is non-toxic to Tilapia. BUT, as the saying goes: it's better to be safe than sorry!
Nitrite (NO2-) — Avoid concentrations greater than 5 mg/L nitrite-nitrogen.
Nitrate (NO3-) — Nitrate toxicity can occur if levels in water reuse systems exceed the 300 to 400 mg/L nitrate-nitrogen range.
Just one more thing. Our "nitrate debate" is primarily academic. In aquaponic systems the nitrate concentration is often very low (double digits low or lower). It's pretty hard to get it even passed a few hundred (unless your system design is poor). Plants uptake nitrogen readily, and it is in fact a nutrient that controls/influences the uptake of other nutrients. The more nitrogen the more you need of everything else in proportion, and the plant will take up as much nitrogen as it can without remorse. It's like crack to a crack addict (or aquaponics to us). In other words, you really shouldn't see the nitrate high enough to harm the fish, period. (we're talking mature system not a new system trying to be cycled, but don't worry about nitrate toxicity in a new system in my opinion)
Nitrate, nitrate, and ammonia levels are all dependent on your aquaponics goals. Any increase of pollutant levels up from zero ppm is added stress for fish. Stressed fish are not happy fish. I don't want to eat unhappy fish.
If you are eating your fish or selling them for food, the water should be as clean as possible. If you are only into the fish part for the veggie benefits the levels can be much higher.
Any increase of pollutant levels up from zero ppm is added stress for fish. Stressed fish are not happy fish. I don't want to eat unhappy fish.
Gee, I dunno Edward. My tilapia were wild caught - captured from a farm pond where they were prey for racoons, otters, eagles, ospreys, herons, egrets, seagulls, pelicans, gators, and big toothy spotted gar. They dealt with near lethal cool water temperatures in the winter, dramatic temperature fluctuations in the summer, near suffocation when the pond dried to a virtual puddle and dissolved oxygen levels plummeted during dry, hot weather and dramatic pH and chemical fluctuations when rain washed mud and organic matter into their environment.
Now, they live in a temperature controlled environment with zero ammonia and nitrites, plenty of dissolved oxygen, no predators to worry about, and all the food they can possibly want to eat. They are even able to have sex whenever and with whatever other amenable fish partner they choose.
Yes, perhaps their dissolved nitrates are higher than in that farm pond they came from (but perhaps not too! - No ag chems, or cow poop and cow urine to deal with now). Regardless, they are a lot less "stressed" than living in their wild environment. They nearly jump for joy when I lean over the tank to observe them or feed them. They seem pretty freakin' happy to me! When their time comes, I'll happily consume them!
They nearly jump for joy when I lean over the tank to observe them or feed them. They seem pretty freakin' happy to me!
They sound happy to me too.
"Freedom is never more than one generation away from extinction. We didn't pass it to our children in the bloodstream. It must be fought for, protected, and handed on for them to do the same." - President Ronald Reagan