What is this?

[Jaydontlag_]

It’s growing on various parts of my tank. It’s fairly easy to scrape off but keeps growing back. Is this some sort of dinoflagelet?

 

[Timfish]

Try siphoning it out instead of scraping it off. This video might help.

 

[lake985]

Looks like some type of sponge

 

[Jaydontlag_]

Looks like some type of sponge

That’s what I thought too but it’s growing all over my rocks and even on some corals. The good thing is that it’s easy to blow off with a turkey baster. I think I might have to change out the filter cartridges on my rodi

 

[lake985]

That’s what I thought too but it’s growing all over my rocks and even on some corals. The good thing is that it’s easy to blow off with a turkey baster. I think I might have to change out the filter cartridges on my rodi

I was just about to ask when was the last time you changed your RODI cartridges. Maybe silicate levels are high?