Infusoria has never made my water cloudy either.
I also use what I call "fresh water plankton" (infusoria, daphnia, seed shrimp, scuds, and FW shrimp) they keep the water clean of that mulm and sludge since many of those are detritavores and actuallly eat that stuff. I keep most of them in a HOT (hang in tank) refugium with Riccia and Java Moss, so they dont take up much space. My fry tank is set up with a carpet of Java Moss, a Moss Wall (in progress) and riccia which helps keep water stable and gives fry and plankton a hiding place to feel secure. Feeding and set up is as simple as putting more moss in the tank
That gives my fry all kinds of menu options. Because the offspring for all those creatures are small enough to be eaten, and since I have a colonies of them, there are specimens of each species in all life stages, so fry grow out pretty well.