Swimming pool - aid? My pool has developed a blue picture around the water splash and...

My pool has developed a blue picture around the water splash and several blue patches on the walls bellow the dampen. It (mostly) comes off next to a good scrub, but the grouting seems to enjoy become impregnated - blue at the waterline and black below.

I live surrounded by Peru, so we get a great deal of sun, but I only hold access to basic chemicals. Any suggestions for removing it?