cloudy tank

Changing half of your water is making the problem worse, as its to drastic a change. The poster who suggest 20% to 25% is correct. Please inform us how long your leaving the fish tank lights on now and is your tank near a window? How much are you feeding your fish and are they eating all of it?

Depends, what color is the cloudy water? Green, that's an algae bloom. Usually the cause is the light is being left on too long, no longer then 8 hours. Or, if you're overfeeding, this can cause it as well. White/grey, that's a bacterial bloom. If it's a newly set up tank, it's common for this to happen and will clear on it's own in a few days to about a week. Stay away from the chemicals, waste of your money, and just not good to use. For either case, be sure you're doing regular weekly water changes of about 20-25%, yes once a week. Thoroughly vaccuum the gravel with a syphon when doing the water changes. Be sure to NOT overfeed the fish. Feed only what they'll eat in 5 minutes, and scoop out the rest. You don't need to change the filter every month, but at least once or twice a month, clean it off in a bucket of tank water. Just rub your hand over it to get the gunk off it. Really only need to change it out every 3-4 months. Here's a link for cycling a fish tank, in case your tank is newly set up. Read through the articles, lots of good info on them. http://freshaquarium.about.com/od/startupcycle/Step_5_The_Cycle.htm

Hi! Have you changed the filter cartridge recently? Those things get pretty filthy. That might help clear up the water. :-)