ID: White Film on Underside of Rocks

[phinatic]

Tank is about 2 months old. This week, I noticed a white film on then underside of the rocks. This film moves in the current and waves somewhat like algae. It does not grow in the light, but on the underside of the rock work or on side of the rocks that do not get hit directly with the light. It has pretty uniformly covered all of these areas. It sort of looks like mulm, but I wouldn't expect that with a tank this young. However, I also have a pod population that far exceeds this tanks age as well, so maybe the conditions are right for it. Water params all look fine. I have a little diatom algae on one area of the sand, but nothing major.

 

 

[phinatic]

Update...I have been checking this under magnification and the white film has copepods (presumably) running around on it. If you look at this pic, you see white dots within the film. These move around and crawl in and out of it. These are the same kind that I see crawling on the glass and on the black overflow chamber.

 

3 hours ago, phinatic said:

 

 

[Woodini]

Potentially natural progression? The weirdos that show up in tanks are ( mostly) fun

[mcarroll]

7 hours ago, Woodini said:

The weirdos that show up in tanks are ( mostly) fun

That's the whole object of a reef to me.  Corals (one of the weirdos) are the attraction, of course.