The newly added rock could be the problem by increasing the bioload, or BL. Limestone has a bioload rating of 2, or BR of 2. This means for every ounce of rock, your filter has to handle 2 more bioload units, or BU. now, a little fish such as a rummynose has a bioload rating of 5, but fish weigh a lot less than limestone. so while a rummynose produces 5 units, a single rock can produce over 50 units of bioload!
To counteract this higher bioload, you need to increase your bio-power, or BP. You can do this via vibration. what I do is silicone some surround sound speakers to the bottom of the tank, so when i'm watching tv, i'm also boosting my BP. Think of ammonia spikes as buildings on a skyline. Now think of vibrations as an earthquake. see how the ammonia spikes go away?
So pay attention to BR and BU to never let your BL get higher than your BP or cloudiness happens , and don't pay a bit of attention to my BS.