While you wait for answers, we may have found some information which could help you.
Click here for Flush Toilet Workshow do I change the bellows in the push button unit for the grohe cistern?
Slow fill of toilet cistern?
The push button on my Grohe Adagio stopped flushing ?
Short burst of water entering cistern ?
Replacement of bellows in Grohe air button?
Grohe 42181 toilet filler valve leaking?