Not to play:
even if you have little ones always supervised, I think the Schloris already too dangerous if you sit by the pool and watching the play.
Because when the children lie down on the pillow or someone expresses it for fun, the air is out and thus the buoyancy away. For such occasions I stay with armbands or if they can swim a little already, with a belt.
Trotzem is an absolute must learn for swimming in my opinion the acquisition.
Make all wet for inflating Schlori, press a corner and blow into the small cavity created. It is then easy.