White Marks?

[crs1945]

How do you get the white marks off the inside of the tank that suction cups leave behind while there are still fish in the tank. The tank is acrylic.Thanks.

 

[Tetra1990]

Sponge on a stick and some elbow grease.

 

[crs1945]

Tried that didn't do a thing!It feels like some of the suction cup actually came off on the acrylic.

 

[crs1945]

No other ideas????