Is this just garden variety algae or something else?

[fredmertz]

Is this algae or just natural dirt/muck?

If algae, any ideas how to clean it off my ornaments/fake plants without taking them out of the aquarium? Hard to scrub the plants.

I have a blue lobster in the tank so none of the anti-algae treatments I have seen are safe.

Thanks!

 

[Alyxx]

It looks like algae or maybe diatoms to me. I would use a soft, clean, lint free cloth to try to wipe it off during a water change. Nothing that has ever been used with any type of cleaning chemical, preferably a new cloth bought for aquarium use only. A strong paper towel could work too. Algae can be tough though, so you may need to take it out of the tank to scrub it with some hot water.