No getting it off, except for emptying the tank, blasting it with light and letting it fall off with a gentle rub. & btw, why is it dreaded.
Where it is growing on the silicone i would just leave it there.
I would presume you calling it 'dreaded' because its chowing up your Ca and Alk?
Warr is this your tank
The thing I am afraid of is, if I nick the silicone and the coralline gets into it. I was enquiring if there any non-abrasive ways of getting it off.
Don't think so, next best thing i recon would be to get a cleaning sponge from the kitchen......
I have a hard sponge magnetic cleaner and this works great on the flat glass, but is no good on the corners.
I think you may have an idea there