Hi,
I noticed last night this white stuff on the back of my tank on the glass. Does anyone know what it is?
This morning it has changed shape slightly and has moved about 2 inches up and to inches to the right, as you can see, its reached the top of my heater now...
I noticed last night this white stuff on the back of my tank on the glass. Does anyone know what it is?

This morning it has changed shape slightly and has moved about 2 inches up and to inches to the right, as you can see, its reached the top of my heater now...
