Is my cycle finished?

hlansford · Sep 20, 2022

Hi! I have a 36 gallon bow front that we are converting to a saltwater aquarium. It has been cycling for about 5 weeks. Ammonia has spiked and is back down to 0....and has remained there for about a week. Currently, nitrites are 2 ppm and nitrates are 40 ppm. Is my tank finished or is there something else I need to be doing to prepare for adding fish to the tank? Thank you in advance. My brain can't seem to keep track of everything I am reading, so I figured I would just come right out and ask.

AFHokie · Sep 20, 2022

If you have no ammonia, but you did previously then you’ve cycled enough to add fish. The bac that converts nitrites will still need longer but the nitrites won’t hurt anything.

Just add slowly as you don’t want to overload the bacteria with more NH3 than they can handle.

mehaffydr · Sep 20, 2022

Yes your cycled. I would do a water change to reduce those Nitrates, Slowly add fish so that bacteria can keep up with increased bioload

vetteguy53081 · Sep 20, 2022

hlansford said:
Hi! I have a 36 gallon bow front that we are converting to a saltwater aquarium. It has been cycling for about 5 weeks. Ammonia has spiked and is back down to 0....and has remained there for about a week. Currently, nitrites are 2 ppm and nitrates are 40 ppm. Is my tank finished or is there something else I need to be doing to prepare for adding fish to the tank? Thank you in advance. My brain can't seem to keep track of everything I am reading, so I figured I would just come right out and ask.

The purpose of a cycle is to create bacteria that will be consuming ammonia and nitrite from your livestock, but you have to get the bacteria from somewhere initially. Its called a cycle because the tank will go through phases of ammonia rising and falling, then nitrate will rise and fall. Once Ammonia reads zero and Nitrate is less than 20ppm, the cycle is complete and livestock can gradually be introduced. The bacteria population will increase with the new bioload, processing waste and converting it to nitrate rapidly. However, it is important to note that overloading the aquarium with too many fish initially can exceed what the bacteria can handle. This is why it is best to add new fish slowly over the next few months.