I bought a couple of these
http://www.aliexpress.com/item/New-F...rchweb201560_9
and 1 of these incase those blue ones were crap and this ones exactly like the petsmart ones that work well.
http://www.aliexpress.com/item/WSFS-...430810897.html
Both work awesome.
And MUCH cheaper then anything you can buy in store here. I bought some 7" bubble wands to go with them instead of the air stones so there is a wider surface area for the bubbles vs just 1 spot.