Another positive attribute of LED Aquarium lights as per s recent study (August of 2009) is that LED used in marine aquariums that suffer with Marine Red Slime Algae (Cyanobacteria) can immediately eradicate Red Slime algae when used in a full spectrum lighting configuration. These "immediate" results were just two weeks.
AquaTop SkyAqua LED 20" R/W/B Aquarium Light, Black (SAQ-20)
With 6 unique LEDs, the German-engineered Marine & Reef 2.0 professional series provides your corals full spectrum exposure for vibrant growth, color and health. Featuring waterproof IPX7 engineering, Marine & Reef 2.0 easily endures regular splashing, and can even sustain complete submersion in the event the unit is dropped under water accidentally. IPX7 also allows the light, with its ultra-slim 1” profile, to be positioned directly above the water surface for better light penetration and efficiency. Several light sizes and mounting options are available, while extendable arms adapt to fit a variety of aquarium widths. An illuminated, dimmable touch switch offers added versatility.
Hexagon Full Hood Fluorescent Aquarium Light - Black - 20 gal.
An example of a 48"L x 15"w x 25"H aquarium (about 80 gal) would utilize (2)Reef White NP 2000 along with either (2) Reef White/Marine Blue 600 or for a more depth penetration but less light spread, (2) Mini 500s could be added to the 2000s.
20 Gallon long- Lighting Level - Aquarium Forum
VHO Fluorescent lights typically range from 75-160 watts and have Kelvin ratings from 10,000° to 20,000°. These lights are very expensive and produce a lot of heat. They require a ballast and/or special fixture especially for VHO lights. They have fans incorporated into the aquarium lighting unit to help keep the lights and aquarium cool. Even though they come with fans you may need to equip your tank with an to prevent your tank water from overheating. These are not as common as many of the other forms of aquarium lighting. So you have a 20 gallon aquarium and need a hood and light to go with it? sounds pretty familiar. When I bought my own tank I found a used 20 long. As I already had plenty of fish keeping experience it didn't take long to have my tank fully up and running with the best 20 gallon aquarium hood I could find. For this guide I will be focused on 20 longs, 30L x 13W x 13H, and 20 talls, 24L 13W 17H. I personally like to give my fish more width to watch them swim but tall tanks allow for different designs and beautiful plant/coral displays.