I found aluminum duct tape at Home Depot in the same area where they carry the sheet metal and HVAC air ducts. I used that roll on an automotive project but will pick up another roll soon.

As far as air stones, the more bubbles the better IMO, I bought the largest ones that they had at Walmart.

And another observation for those building a system - its better to go to Lowes or Home Depot and get the black vinyl air line tubing rather than clear vinyl stuff so that you don't end up with algae growth.