Do You Need To Cycle A Frag Tank ?

Conventional reefing wisdom states that a reef tank must be fully cycled before adding fish or corals.  While this statement is certainly true for traditional display tanks is it the same for frag tanks?  Do frag tanks really need to be cycled? The answer to that question is somewhat complicated.  Certainly frag tanks do need to have ammonia and nitrite readings of zero before adding fish or corals.  However, the process to get them to that point is generally different from how reefers cycle a traditional tank.


When cycling a reef tank, most hobbyists will use a combination of additives, such as those available from Reef Casa.  While this method is highly effective, the tank’s cycle will still take a few weeks and it may be a couple of months before the tank is ready for sensitive corals such as acropora.  Since most salt water enthusiasts who are setting up a frag tank likely already have a thriving display tank the process is a little bit different.  First of all, since frag tanks will generally not contain a sandbed or rockwork there is less surface area for beneficial bacteria to populate.  To compensate for this, most reefers will choose to use bio media in the rear chamber of frag tanks in order to provide a place for bacteria to multiply.  By using media from an established tank this process can be sped up significantly.  Similarly, using water removed from an established tank during a water change to fill a frag tank is a great way to add beneficial microfauna.  Even a small piece of rock from the established tank can be placed in the frag tank for a few weeks to kick start the cycling process.  Adding commercially available beneficial bacteria can also reduce cycling time.  Using a combination of these methods, a frag tank can generally be cycled in a much shorter time frame.  Having said all that, it is still important to ensure that ammonia and nitrite levels have reached zero before adding corals and fish in order to ensure their long term health.  If you have any questions about cycling your new frag tank please reach out to us, we are happy to help!