Where can I find commercial hydroponic supplies?

If you live in a larger city, you might be able to find a business which specializes in the sell of commercial hydroponic supplies. However, most often the best place to find such a business is online. Several companies provide supplies for hydroponic gardening (small and large scale), such as www.hydro-gardens.com, www.amhydro.com, and www.commercial-hydroponics.com.