Cloudy water

[akma0620]

I have a 55 gal fish only marine tank. The water was cloudy, so I did a 20% water change and checked the following last weekend:

ph=high 7.0
ammonia=0
nitrate=0
nitrite=0

But the water is still cloudy. Do I need to replace the carbon in the fluval filter? I have a yellow tang that's been breathing heavily in the last several weeks. Could the heavy breathing cause by the cloudy water or low ph?

I'm adding marine buffer to the tank to bring the ph to 8.3 now.

Thx,
Adrian

 

[kreblak]

If your activated carbon is more than 3 month old, then you should definately change it. Do you run a protein skimmer? Skimming might help with the cloudiness. Low water PH is sometimes a result of dissolved nitrate buildup in the water. In turn, high dissolved nitrate levels are often the result of inadequate water changes. If your water level readings are correct and your nitrates are really 0, then there must be something else clouding up the water.

Do you have above normal algae growth on the aquarium glass? Brown algae in particular on the glass can make the water appear cloudy or dirty. That might be a long shot, though. What do you have in the tank besides the yellow tang?

One final note, have you checked the tang for small (pinhead sized) black spots on his body or fins? If you see any, especially behind the gills, the tang has black Ich, and that is why his breathing is labored.