Cycle

Question
Hello.  Recently I received a 46gl marine tank from a friend. The water had been cultured for over a year to include live rock. The unit came with a sump & pump unit; however the bio balls had dried out and with my little toddler fiddling under the tank stand i was forced to buy a normal bio filter (hanging on rear of tank) along with skimmer and aeroator.  As soon as I received the tank I had the water tested and Ammonia levels were at 0%. Throughout the week, I've been testing the water and noticed slight increases in ammonia; did a water change and that seemed to help abit.  The bio filter has been running for a week now. Because I started a new filter does that mean the water is going to cycle all over again or since there's already 85% pre-cycled sea water already in the tank to include live rock and sand should I need to worry before adding fish like a coral beauty? Thank you.

Answer
HI Kevin. A great deal of your good bacteria is contained in your filter. these bacteria grown on every surface of the tank that has a good amount of water flow but are not in the water. Changing filters will destroy these bacteria and will cause a tank to go through another cycle. When switching to a new filter it is best to run both filters for a about a month before you take the one you are doing away with off. I would not add a coral beauty to a tank that is going through even a slight cycle. The filter needs to get seeded and it should do this a lot faster than the initial cycle of a new tank but you should test your water for ammonia, nitrite and nitrate at least every other day to see where you are. Coral beauties are prone to all sorts of problems if water quality is even slightly off. I think you should wait until your filter is able to handle the small load you have before you put any fish in there.