How do I get this stubborn mark off the bottom of toilet?

[Jemster]

I've tried bleach and harpic strongest cleaner but there is still a mark on the base of toilet so it looks like it hasn't been cleaned. How can I get this off?

You need to get rid of all the water first so the product isn't diluted. Pump it round the bend with a brush.

The Harpic tablets are good.

My mother in law gave me a handy tip use the original harpic not the super strong just plain old original as its better than the others (tis true!) and I also second harpic tablets

Also if you are in uk my DM says Sainsburys own toilet cleaner... Best she's used. She's a cleaner