If you guys are looking for cheap bubbles by the ton made by Venturi's, check out protein skimmers and their pumps. I've been thinking about using one in my dwc but don't quite know how to incorporate it easily into my setup yet. A bubble blaster pump cost about $150 on eBay and will turn a 5 gal bucket into bubbles so thick it will look like milk .

Also you guys were wondering what the seal is called that you used when you drilled a hole into the bucket, it's a bulkhead so search 1" bulkhead and you'll find what you need

Here is a skimmer that I have. Notice the way the water looks inside the reaction chamber.Attachment 290058