Need help On ID, random weed, growing in hob.

[markstrimaran]

Small 1/4" flowers, sunflower like seed cluster. 20 days of growth,

Mostly, trying to figure out if my cats, will get sick if they eat some?

It just started growing, on its own.
The media is a foam air cleaner from my 6.5 diesel, that's been all over the western states, and has been repurposed.

 

[markstrimaran]

It's still unknown, growing only on fish tank water.
No dirt. Course foam and moss.
It has small white flowers, sunflower like. I have no idea what kind of plant it is.