Expert: Richard Hight - 10/22/2009

Question
QUESTION: We just recently cleaned our fresh water aquarium which we have had up and running for about 5 years.  We also just introduced three new fish and a small frog (which we have never done before)  Along with those two changes, we added a rock pack to our filter which already had a carbon filter pack and a sponge.  Now our aquarium is really cloudy.  What can we do to remedy the cloudy water and clear it up again?

ANSWER: Hi Paul

The cloudiness you are seeing is a bacteria bloom.

When you say you recently cleaned your aquarium, what exactly did you do? What I mean is, did you completely tear it down, drain 100% of the water and refill it? If you did, you killed all of the beneficial bacteria causing your tank to cycle again. This type of major cleaning should never be done.

You should never change more than 30% of the water at one time, siphoning waste out of the gravel with a gravelvac and clean the decorations in the water you siphon out. This maintenance needs to be done every week.

Another thing that could've sparked the bacteria bloom was making changes to your filter. Some filters allow for additional and optional media content, but these should be setup in the beginning.

The only thing I can suggest you do for now, is to perform small frequent water changes (10-15% every couple of days. If you did the major cleaning I talked about, your going to have to let the tank complete the cycle period again before it will clear up completely. It usually doesn't take quite as long the second time. 2-3 weeks probably. Feed your fish sparingly during this time. Replace the carbon in your filter once a month.

You can add fish to your tank at any time as long as you are not overcrowding your tank. But outside of the weekly maintenance I mentioned above, you shouldn't make any major changes to an established tank.

I hope this helps you, good luck!

Richard

---------- FOLLOW-UP ----------

QUESTION: Thanks Richard. I did not do the whole-tank cleaning that you warn against. I knew that that was a bad idea. I did, however, add another element to the filter system. Oops! What should I do with that now? Should I leave it in the filter or remove it? Should I proceed with the 10-15% water-replacement that you recommended?

Answer
Hi Paul

You're very welcome! If your tank has been running trouble free for 5 years, I would remove the additional filter media you added. This may help clear up the water. If not, then yes, I would do the 10-15% water changes every couple of days until the tank settles down and the water clears.

Hope this helps, good luck!

Richard