Help identifying bacteria/film on water

[Sablah]

There's a slimy film that is forming on top of the water in the return area of my sump, and I think its also starting to grow under the waterline on the wall of the sump in the return area. It just barely has the shimmering look to it like gasoline/oil on water. When on the water, it looks like a cloudy light brown color. When I scoop it out, it forms into a long, stringy snot like substance, and is pinkish red. After cleaning it off the surface, it takes about 2 days before it grows back and is covering the surface of the water in the return area. When I clean it out, it kind of breaks apart into almost flaky pieces, and will eventually form into a snot-like substance when the pieces collect together on the return pump underwater.

The return area just has the pump and I have a GFO reactor emptying into it. I noticed this stuff has grown in some areas of the plumbing going into the sump, but no where else.

I bought this tank two weeks ago from a guy that was moving. He said he did not have this issue. Any ideas what it might be?

In the first picture, circled in red are two dense patches of it. Ignore the bits of sand in the bottom (I circled examples of the sandy bits in blue, since the sand kind of looks like bacteria growth).
In the second picture, you can see that it the whole surface is covered and it is reflective.

I'll try to take a picture of it in its snotty form next time I clean it out.


PH: ~8.0
Alkalinity: 7.2dkh
Phosphate: ~0
Calcium: 420
Temp: 77.7-78.4
Nitrate: ~0
Ammonia: <0.1
Magnesium: 1140
Salinity: 33ppt

 

[Sablah]

I just tried to get as much as I could out (I already cleaned it earlier today and forgot to take a picture) and this is what it looks like. The thicker it is the more pink it gets. It'll come back and cover the surface in a day or two, and I'll post more pictures.

Also, I think its clogging up the foam filters in the baffles of the sump and causing high water levels in the skimmer area, and low water in the return area. I've taken the foam filters out for now so the water level stays consistent.