One of our most asked questions is, which LED Aquarium Light should I get? In this quick guide I'll give my recommendations. Definitions: Low light = Undemanding plants, Anubias, Crypts, etc. Medium Light = Stem plants and most other plants that aren't carpeting High Light = Can grow virtually anything, really does best with CO2 added. Small Size tanks:2.5 Gallon Tank - Clip on Stingray Light - Medium to High Light5 Gallon Tank - 16 inch Stingray Light - High Light, Clip on Stingray Light Medium10 Gallon Tank - 20 Inch Stingray Light - High Light15 Gallon Tank - 24 inch Stingray Light - High Light20 Gallon High Tank - 24 Inch Stingray Light - Medium Light - 24 Inch Fluval 3.0 - High Light20 Gallon Long Tank - 30 inch Stingray Light - High Light Medium Size Tanks:29/30 Gallon Tank - 30 inch Stingray Light - Low-Medium Light - 24 Inch Fluval 3.0 - Medium to High Light40 Breeder Tank - 36 inch Stingray Light - Low Light - 36 inch Fluval 3.0 - Medium to high Light40 Long Tank - 48 inch Stingray Light - Medium Light - 48 inch Fluval 3.0 - High Light55 Gallon Tank - 48 inch Stingray Light- Low Light - 48 Inch Fluval 3.0 - Medium to High Light65 Gallon High - 36 inch Fluval 3.0 - Medium Light - 2x 36 inch Fluval 3.0 - High Light75 Gallon Tank - 48 inch Fluval 3.0 Medium Light - 2x 48 inch Fluval 3.0 - High Light Large Size Tanks:90 Gallon Tank - 48 inch Fluval 3.0 - Low Light - 2x 48 inch Fluval 3.0 - Medium to High Light120 Gallon Tank - 2x 48 inch Fluval 3.0 - Medium Light 3x 48 Inch Fluval 3.0 High Light125 Gallon Tank - 2x 36 inch Fluval 3.0 - Low Light - 4x 36 inch Fluval 3.0 Medium to High180 Gallon Tank - 2x 36 inch Fluval 3.0 - Low Light - 4x 36 inch Fluval 3.0 -Medium Light240 Gallon Tank - 2x 48 inch Fluval 3.0 - Low to Med Light - 4x 48 inch Fluval 3.0 - Medium to High light