I think you need more filter horsepower. This will reduce any suspended 'granular' particles that are clouding your water.
If you think your cloudiness is caused by a bacterial bloom, increase airation, lower the temp and cut back on food until it clears.
Keep your mechanical filters clean but dont upset your biofilters until the water clarity is where you like it.
Carbon works well to remove organic molecules disolved in your water. Things like dyes, some weak acids (tanins etc), and medications especially. This usually has a clarifying affect on the water that can be noticed within hours of adding it to a filter. I use it in all my tanks because I have hard buffered water with a pH of 8 and therefore am not worried about tanin removal.
If you prefer soft acid water, carbon may not be a benefit to you if you run it all the time.