I would suggest a partial water change to start with (never more than 25% at a time). Water should be partially changed every week(about 10% per week up to 50% a month). Filtered water only or pour the water in a bucket and let sit overnight to let the chlorine compounds evaporate). Water conditioners work well to instead of or in addition to filtering When was the last time you replaced your filter media? This usually needs to be done once a month. Try a product called Chemi-pure as a carbon substitute, I have been using it for years and it is a fantastic product. The cloudiness could be due to a number of things, including ammonia buildup. I would also suggest using a bacterial additive to help the nitrogen cycle. Do your fish look sick? Any growths on any of the fish or missing parts of fins? If so, you may have a fungus attacking the fish. There are several good products for that as well. Good luck!
