Official web-site of the South African Department of Water Affairs www.dwaf.gov.za

Endangered Wildlife Trust www.ewt.org.za

American Water Works Association www.awwa.org

Aquaculture Association of South Africa   www.aasa-aqua.co.za/

Aquaponics   www.aquaponics.com/

Hydroponics  www.gtghydroponics.com/faq/hydroponics.htm

Lovibond international site   www.lovibond.de/

Metric Conversion Chart  www.engnet.co.za/tips/convert.asp

Clickable Chart - Periodic Table of Elements
www.goldenkstar.com/periodic-table-software-school-chemistry.htm