the only thing i can think of is i got a bigger water pump. my old one was for my 55 gallon tank and i got a bigger one. it pumps about 800gph. would that make a difference. it was fine before as far as i remember but my old pump broke so i decided if i had to get a new one prepare for a bigger tank also.
Possible if it changed the water flow. You may be getting more flow, meaning more gunk gets pushed out from the rocks and sandbed and voila, it's now sticking to your glass and equipment.
I had a similar problem when I added a Seio M2600 to my tank, in addition to my M1500. I got a bunk of gunk kicked up and it stuck to the glass, so I just scrapped it and let the skimmer take it out of the water. It cleared up and never came back, so no long term worries