Aquaponics- Live Fish Cycling

Our system is complete (I’m still working on a few leaks but nothing major). My advice: when building the barrel-ponic system be sure to use PVC glue and silicone in large quantities (wait 24 hours before adding any liquids) – avoid leaks!!!


We’ve picked up about 10 Tilapias and 5 Sambos from a local friend living in la Costa Del Sol (El Salvador) – a few of those are pregnant – so we’ll be careful not to have too many fish in the tank. We’ll try to keep the ratio at 1 pound of fish per gallon (and we’ve got about 20/30 gal of water at any given point).

As the fish are now in the system – it’s time to do go through the cycling process. Which is the creation of the bacteria that transforms the ammonia (fish poop) into nitrites and nitrates. During this process we want to be sure to add water as required to avoid our tank becoming toxic to the fish.

We’ll be raising the ammonia level – adding water and repeating this process until we reach a non-toxic tank. Once you detect nitrates in your water and the ammonia and nitrite concentrations have both dropped to 0.5 ppm or lower, your system will be fully cycled and aquaponics will have officially begun!

During this process we had to test the water every 2 days. 

(when adding the fish it is recommended to float the fish bag on top of the tank for 15-30 min and carefully open the bag – this will bring the water temperature to the same level).

Truth be told – our fish had a really hard day being transported in a local bus for about 8 hours. We added some clean drinking water a couple of times but our 15 fish (were in two 2.5 gallon bottles) and didn’t really get treated as they should have. And we dropped them in the fish tank without any special care. The good news is that we’ve got some really resistant fish and 24 hours later their swimming happy as ever in our fish tank.

If cycling the tank without fish, you can do this (nitrogen dosing) by adding a nitrogen source such as pure ammonia, urea (1 tsp per 1000 L) or fish food. The tank is ready when the nitrogen & ammonia levels have exceeded 4;5ppm and then returned to 0.

Aquaponics El Salvador