Newbie - Advise needed....

Got a question to ask you guys. Since posting I have done another water change (Last Monday 12/26) and even thou brown algea has stayed the same I now notice today especially that the water is cloudy. I have checked water parameters and all except for Phosphates are fine. Phoshates are 0.5ppm which is kinda high. Overall I have only added phosban to lower phosphate levels but it seems water is getting cloudier and it has a nasty smell to it. Corals and fish seem fine and healthy thus far but would appreciate help or info as to what this is. Is this normal??