Odd things in my sump?

[aquaria]

So i was looking at refugium today and found brown dots all over the walls of the sump and mainly on the silicone. There also was quite a large amount of coraline algae starting to bloom and that has decreased a decent amount over the last couple days!
Ph- 8.2
TRATE- 15
Phos- 0
Ammo- 0
TRITE- 0
I have a chuck of culerpa in the Fuge with a little bit opt Chaeto i found growing the other day
Any ideas?
Thanks!

 

[reefkprz]

A photo of the dots would help immensely I can think of a half dozen things they could be offhand. at least a better description is needed. google images of flatworms that would be my first guess though.