Lighting is essential for the aquarium. It is an integral part of enjoying the aquarium. But lighting has become a very complex issue. The number of options has become huge. The old fluorescent tube aquarium fixtures have become a thing of the past. The new LED fixtures have taken over. Each of these fixtures has 20 to 100 small (typically 3 watt) LED lights in a multitude of colors.
The simplest and cheapest LED lights are “all white” LEDs. These “all white” LEDs have some significant shortcomings. They do not have the blue and the crimson red colors needed for good plant growth and good color on some fish.
One must look at the spectrum of LED lights to get the best. To get the best combination of fish color and plant growth one needs three types of LEDs in combination: daylight (most cheap LEDs), crimson red and blue (“grow lights”). If you only use the cheap shop LEDs for instance, your plants will not thrive and your electric blue Fryeri and your red dragon blood peacock will not have good color. Use only grow lights (crimson red and blue) and everything in the tank will be purple and your yellow Lab will have no color.
An aquarium LED with 15 to 25% red LEDs and 15 to 25% blue LEDs will cover the full spectrum and duplicate sunlight. This will give the best plant growth and the best fish colors. Combining a shop LED with a smaller violet grow light LED set also works great.
Note that a high tech planted tank with very high lighting needs crimson, blue AND WHITE light. Only blue and crimson light is not optimum in high light conditions. Recent research has shown that the pigments which absorb green light (red and orange pigments) function to protect chloroplasts at high light intensities and give energy to the chloroplasts that they can use.
Then there are some non-programmable aquarium LED lights which have roughly 80% white LEDS, 10% blue LEDS and 10% red-pink LEDS. These are a very good option for the aquarium.
The most advanced (and most expensive) LED lights are computerized with four programable timed light channels that can vary the amount of white, blue, green or red-light present over time with remote controls or even WIFI cell phone controls.
One can program in a blue-red combo for when the owner isn’t around to maximize plant growth. Then a normal spectrum can be programmed in for when the owner is there since the normal spectrum is more pleasing to the eye. Gradual increases and decreases in light can also be programmed in to duplicate dawn and sunset.
It is important with LED lights to isolate the lights well from the moisture inherent in most aquariums, especially spray from an air stone. When the bubbles of an air stone break the water’s surface, they form what is known as an aerosol of fine water droplets which drift upward into the circuitry of the LED lights. This corrodes and shorts out the lights in short order.
Suspending the LED lights more than four inches above the aquarium can lessen the problems with circuits shorting out. An airflow through the LEDs is also useful in preventing moisture problems. A computer fan can be used to create an airflow across the LED lights with a very low noise level.
The “strength” of a given LED light is best looked at from the standard of actual watts multiplied by eight. If an LED grow light has an actual wattage of 13.5 watts, then its relative strength is 8 x 13.5 = 108 equivalent watts.
Obsolete Light Standards
With the advent of LEDs, some of the old standards have become largely obsolete. The standards include lumens, PAR and degrees Kelvin. More about obsolete light standards in this link:
14.4.2. Obsolete Light Standards
More about the important spectrum of lights in the following Pages:
14.4.1. The Spectrum of Lights