Do you think these are hydroids?

[Adamantium]

Any thoughts? They seem to only be on the undersides of my rockscape.

 

[cloak]

+1 Hydroids

 

[Adamantium]

+1 Hydroids

Any insight into how I can deal with them? Keep nutrients lower? Stop dosing phyto? Right now NO3 is only 5 and Po4 is .04.

They’re pretty in check, but I’d like to avoid them getting worse.

 

[cloak]

As long as they're not taking up any prime real estate I wouldn't worry to much about them. If you want though you could get a stiff brush and give the rock a good scrubbing right before your next water change. GL.

 

[Adamantium]

Thanks! I’ll leave them, then, and maybe pull back on phyto dosing to try to keep them in check. I’d hate for them to inadvertently spread if I scrub them.