A Cycled vs Mature Aquarium
To distinguish between the two we must go all the way to the beginning, the very first thing you do when you have your tank set up... At first you start out with nothing but the equipment. You have your tank, your filter, a light and hood/fixture, maybe a heater or chiller, your saltwater is all mixed up and you've filled your tank with it and some decorations perhaps. But it's not an aquarium yet, there's absolutely nothing in your tank that's alive yet!
The very moment that you put a living organism into your aquarium you begin the cycling process. But what is the cycling process? Simply the cycling process occurs when a living organism produces Ammonia as a waste product, which could be from excretion or death and decomposition in the aquarium. The cycling process is the process in which bacteria forms to break the Ammonia (bad and harmful to aquaria) down to Nitrate (or even to Nitrogen gas - which then leaves the aquarium).
