Changing filter media to often?

You are definitely changing the filter media too often, perhaps once every 3 or four months. however, NEVER, EVER change ALL filter media at the same time, Since you have two filters, do one filter at a time, wait a month, then change the other one. This is probably the reason your tank is cloudy, Why? because you're eliminating the very important bacteria that grows in the filters that eliminates ammonia, nitrites, and nitrates (You SHOULD know about this) causing your tank to go into a cycle or mini-cycle (explains cloudyness, also known as "Bacterial bloom". Also, every time you change the water, you should vacuum the gravel.