Can I Kickstart My Cycle with Aquarium Water?

Q: I’m a newbie aquarium hobbyist and just starting to set up my first tank, which will be a 40-gallon soft coral reef system with a few small fish. A friend of mine, who is also fairly new to the hobby but already has an operating tank, explained the importance of cycling to me. I’m not sure I really grasp all the ins and outs of the process yet, but I do understand that I need to get certain bacteria established in the tank to convert ammonia to less harmful substances. My friend has offered to give me several gallons of water from his tank when he does his next water change in order to help me cycle my system. Will that be enough to get the cycle going in my tank? -Nathan Kranz

A: First off, welcome to the marine aquarium hobby, and kudos to you for seeking advice on the vital process of cycling during the setup phase of your system rather than rushing out and buying livestock right away like so many newcomers do. With respect to your friend’s kind offer, the beneficial nitrifying bacteria that convert ammonia to nitrite and then nitrite to nitrate are not present in significant numbers in aquarium water. Rather, they colonize the rockwork, substrate, and other hard surfaces in an aquarium system. MORE

Saltwater Smarts is a unique online resource created by long-time aquarists Chris Aldrich and Jeff Kurtz to inspire and entertain a new generation of marine aquarium hobbyists while helping them acquire the reliable, authoritative knowledge base they need to succeed with a saltwater system. By clarifying key concepts, techniques, and terminology, as well as sharing expert insights from fellow enthusiasts and industry professionals, Chris and Jeff hope to promote a more accessible, sustainable, and enjoyable marine aquarium hobby. Read more about our mission and the contributors who are part of our team.