DIY Doctor UK DIY Forums

I have a new bifold shower screen, and the problem is after showering and cleaning and screen etc after awhile a build up of small white particles[which i believe could be calcium] appears on the inside of bottom runner which in turn makes the opening and shutting of the screen to be stiffer and not smooth, i have to use a toothbrush[an old one] to clear the stuff to make it slide!!!
any ideas of what i need to do to avoid it.
many thank's