I have not been able to get clear water for quite some time. Fresh or saltwater.
Is the water from the tap cloudy? If so I would suspect fluorines. How well is your skimmer working? If it's collecting alot of fluids there could be a foreign substance in the water causing your problem or the saltwater is not being mixed long enough prior to adding to the tank.
They seem to be happy as can be and cycle seem great.
This part may also suggest a possible cause. If the tank is still new, this many fish added to an improperly cycled tank could be causing continual bacterial blooms. How's the water paramaters? NH4
? Feeding twice a day is also not needed. They only need feeding once a day at most or even every second day.
Since you've indicated there have been no chem additions, you might try looking for equipment causes such the outflow to the power filter. They primarily point straight down so it could easily be aggitating the substrate. While on that topic, I would honestly suggest an additional PH
. The main water mover you have being a HOB
is not all that efficient.
Have you tried a good grade of carbon to see if it helps remove the particulates?