Water Clarity...strange?

[Tiger Tiger]

Hi
I first had a 75 gallon tank full of cichlids which had sand as a substrate and plenty of ocean rock and everything was fine with the water you could see your face in it..
I swopped everything over recently and now I have black/green/blue gravel with bogwood flint and live plants. Now the tests show everything is fine, nitrite nitrate ph etc but the water is cloudy?
It’s not cloudy in the sense of bits etc like waste but it is like a pure fog?
What do you think is causing this?
Like I said all tests are good and the fish lively?

 

[Syphoniera]

Hi, Tiger Tiger,
Speaking as a non-expert, it sounds like a bacterial bloom - also, I notice that ammonia testing was not specified in your description.
Beneficial bacteria colonizes every non-plastic surface in your tank, and gravel provides the largest repository.
Changing out the gravel has removed a great deal of nitrifying bacteria, so nitrite levels may not yet show as increased, but an ammonia spike is nonetheless likely.
Personally, I'd do small, frequent water changes, plunk in more live plants, if poss., to help suck up ammonia, and keep a close eye on the situation.

Edit - if you have lots of live plants in and they're growing, the ammonia may be removed as it's produced.