(First Post!) I've had fish tanks for a few years now and I recently had to dump and start new on my 20g tall cichlid tank. When I put my tank back on my stand the front now faces the back and where my Penguin 200 BioWheel filter sat is a calcium build up on the inside of the tank on the actual acrylic. I've tried to scrub it off with the normal cleaning pad to no avail and was wondering if anyone had any ideas. I live in California where the water is very hard and I'm currently treating for Ich thanks to a couple of new additions from my LFS
. Any help on this one would be greatly appreciated, I can't seem to get this calcium out.