Help with Sponges

[Velezdav]

Hello , i been having allot of sponges growing on my display and dont like how it looks , is there is a way other than scraping it out to get rid of this , i am in the point of ******** down this tank …
Thank You

 

[Spare time]

Possibly check for silicates? Some angels eat sponges (and some dwarf angels).