yl79 - we had 2 lots but they all came to a messy end ie: dd2 and dd2's friend deciede to pick th econtainer up by the lid.
I think their is probably enough room for 8 in the piddlly plastic thing. If you got something bigger you would need to buy some more of the salts for the water.
From my exp 8 is a good number to still have since christmas.