Cycling if adding new substrate sand

[Lamie]

Do I have to cycle the tank if I want to add a bit of sand to the bottom of my tank? (I thought I read that had to cycle)

 

[Fishmanic]

If your tank is already cycled, there should be no need to cycle it again if adding sand. But say you add too many additional fish, that might cause a mini spike in ammonia and interrupt the cycle for a couple of days till the beneficial bacteria grow to compensate the increased load.

 

[outofwater]

If your tank is already cycled, no, adding sand doesn't mean you have to cycle again. Just make sure you rinse the sand well before you add it.