bosch 1400 excell WAE28465GB/05 washing machine?

F18 on screen: I have released drain pump hose and open cap to release water, this I have done again to release water.
I have removed cap from behind service flap and clean in there and propella just has gritty bits in again (possibly limescale). I then put it on spin withh cap still off and propella thing is spinning fine?
just put it on a 90 degree wash. unsure what to do next? help please...