Im no expert, but i would check water paramaters and that will probably reveal the problem. without knowing for sure whats causing the cloudy water (other than a massive bio-load from cats and oscar) its impossible to recommend a solution.
I would check ammonia, nitate/nitrite.
Then go from there to fix the cause of the problem.
Im guessing that its just the massive bioload causing paramaters to go outta whack which may be able to be fixed with some added bio filtration. but check water first.
Cats and Oscar? Those gars drop deuces literally the size of my index finger lol.... Thank you for the very detailed feedback i appreciate it man.