The best place to start is to explain the nitrogen cycle that takes place in an aquaponics system. We start with the fish. Now you might think that fish are the key to making aquaponics work, but you would be wrong. The real key is ammonia, without the ammonia there is no nitrogen cycle. Ok, ok, what about the fish right? Well as the fish go about their day, they produce a fair amount of ammonia. They breath through their gills, pee and poop, all creating ammonia. Now ammonia is toxic to fish and most other living creatures, so if the ammonia levels get too high, say 0.5 to 1 ppm or so, the the fish will die. Luckily for the fish, a bacteria called Nitrosomonas can convert ammonia into nitrites through a process called nitrification.
Nitrification is simply a conversion of ammonia to nitrates. Before you get on my back, I am fully aware that I said that Nitrosomonas converts ammonia into nitrites and not nitrates. The nitrogen cycle is a 3 step process and nitrites to nitrates is the last step, so lets not get ahead of ourselves. We need to focus on the first step, introducing ammonia into the system.
We know that in order to begin the nitrogen cycle we need ammonia. This is where the fish come in right? Well that would be one way to go. It is a method called fish cycling. This is where you add a few fish at a time to produce ammonia. If the fish are lucky, the nitrogen cycle completes before the ammonia levels become toxic. In order to reduce the toxic ammonia build up, some of the water is removed and fresh water is added to the system. In this attempt to restore balance, significant stress is placed on the fish and loss may occur. Eventually the nitrification will take place and you will end up with a balanced aquaponics system. In order to avoid fish loss, an alternative method to fish cycling is fishless cycling.
Fishless cycling is where you find a source of ammonia other than fish waste. There are many sources of ammonia that can be added to the system, I have even heard of people peeing into the fish tank. I am sure the fish really want to live there after that, gross. I just use pure ammonia from the drugstore. You have to make sure that its only pure ammonia and not ammonia mixed with detergent, because the detergent will kill the fish. Finding a nonliving source of ammonia to use for cycling offers us many advantages over using fish. In my opinion, the greatest advantage is the speed we can cycle the system. Because we can raise the levels of the ammonia quickly, we decrease the time necessary for nitrification to occur. Fish cycling can take weeks for ammonia levels to increase to a desirable amount, whereas fishless cycling allow us to raise the ammonia levels to 0.5 ppm immediately. So, with fishless cycling we are able to jump start the nitrogen cycle by raising the ammonia to toxic levels without killing any organisms. This is where we begin week 1 of cycling our aquaponics system.
Follow these simple steps for the first week of the cycling process:
Add the ammonia to the fish tank a few capfuls at a time.
After you add a dose of ammonia to the system, take a reading with the ammonia reading kit.
When you read an ammonia level of 0.5 ppm, take note of how many capfuls it took to get to that point.
Add the same amount of ammonia each day, then take a reading with the nitrite kit.
When you see a nitrite level of 0.5 ppm begin to appear, cut back the daily dose of ammonia by 50%. This will decrease the levels of ammonia in the system making it more hospitable to your future fish.
It will take about 7 to 10 day to reach this point. Stay tuned for the next video that will outline the next steps to cycling your system in week 2.