I worked for pool companies back in the 70's while in college and after work. Some things have changed, including filter balls I have no experience.
I can tell you the fine cloud is not unusual with any filtration type.
If the multiport valve is in good shape and not allowing unfiltered water to bypass I suggest super chlorinating then shutting off after running 2 to 3 hours (to make sure chlorine gets mixed in. Let it set for a day unfiltered. Vacuum bottom of pool to waste, back wash filter, then run in normal filter mode. See how that does.
There is a process called floccing that adds a chemical that will cause the fine sediment (cloud) to clump up.where it can be removed by the filter, or again let it settle out and vacuum to waste.
Vacuuming to the filter media will only re-insert fines to the filter only to later be returned to the pool. Idk if a floc agent can be used with filter balls so check on that first.
In any case if floc is used and every time you do not vac to waste backwash right after vacuuming.
Seeing the material in a cloud at the bottom, and as is settles out it is likely a mineral/crystallization issue. Have you ever drained down the pool 1.4 and topped it off. Sometimes pools fall out of balance over time with evaporation and topping off, along with added salts from liquid chlorine.
A detailed water analysis may help.