Alden Leeds (Popularity: )
http://www.aldenleeds.com/ Provides several full lines of swimming pool chemicals to the professionals in the pool business.
BioGuard (Popularity: )
http://www.bioguard.com A manufacturer of pool and spa chemicals. Site includes problem water troubleshooting and pool triva monthly contest
Coral Seas (Popularity: )
http://www.yellowout.com This site features information on Yellow Out, a ecologically-safe algae cleaner. Detailed information is also included at this site.