What are these? Pictures from under the microscope

[ReefIO]

Hi, I have two different subjects that need ID-ing.

First,
I've been battling Amphidinium Dinoflagellates and have been dosing Silica (Brightwell's SpongExcel) to encourage diatoms.
Here's the first shot. Looks to me like possibly pennate diatom. Thoughts?





Second,
Just recently dipped a coral and a few of these worms fell off. They look pretty neat under the microscope. Any idea what they are?

 

[taricha]

first are diatoms. Probably something like cylindrotheca (google pic)

second is probably a dorvilleid worm see fig 12

 

[ReefIO]

first are diatoms. Probably something like cylindrotheca (google pic)

second is probably a dorvilleid worm see fig 12

Wow!! I think you're right on both!! Thanks for your help!