Intermittent slime floating around DT

[gregzz4]

Last month I posted this issue as I suspected my ATO water was the cause, but now I don't think this is the case
I get slime in my DT, but not my QT, and both have Osmolators supplied from one ATO holding tank

In my DT, every now and then, I see bits of slimy, whitish-clear looking stuff floating around
It kinda looks like broken bits of cellophane or such, waving around as it circulates throughout the tank, and once it goes through the MP10s it gets shredded and eventually disappears

I have numerous lengths of food-grade vinyl hose in the return section of my sump that develop a slimy feel to them, but doesn't this happen to everyone ?

Anyone else have this happen ?
Any suggestions ?