Don't clear floor 30+ in castles until the Gem Collection event starts

There’s a Gem Collection event coming up (starting August 16th at 0700 UTC - you can see it in the events list if you scroll to the end) - so if you haven’t yet cleared floors 31 and higher in the castles (but are strong enough to get there), target clearing them during the event.

And if you are currently at a lower floor, play up to level 30 before the event starts.