Lighting is usually mistaken for not being important. You need the right kind of lighting for for what aquarium you have. Too much lighting can lead to algae. For example, in a planted aquarium, you have to keep the co2, lighting, and nutrients/fertilizers even in order for the plants to grow. If lighting is too high, the plants won’t take in as much light so the excess light will be absorbed from algae to grow. Also, keeping your lights on too long every day can cause algae. For planted aquariums, a 8 hour photo period is good while other kinds of aquariums can have a photo period of 12 hours. Let’s say maybe you don’t have any plants in your aquarium. No problemo. Just focus on the color temperature of the light. This can be measured by kelvins. Usually, the higher the kelvin, the more blueish tint it has and the lower the kelvin, the more reddish tint it has. Planted tanks should use 6500k lighting which is in between the kelvin ratings. Lighting below 6500k gives a more reddish tint. Red isn’t the best color for aquariums because too much red usually causes algae but also a good source for plants to grow. Plants use the red and blue colors of lighting while the yellow and green is reflected off.This is a graph of a popular planted aquarium light.
In this graph, you see blue’s intensity is higher than the other colors since plants absorb blue. Red is also absorbed by plants but it has low intensity since too much red is also a good producer of algae. Yellow and green are reflected off. In aquariums without plants, use a light with more blueish white tint like 10000k. Here’s some aquariums with different kelvins in their lighting.14000k lighting is so blue it’s used for saltwater aquariums since corals need a blue light. 10000k lighting is good for most types of aquariums but not recommended for planted. Algae won’t be much of a big problem since the light is mostly blueish white. 6500k lighting gives off some red tint. It’s best for planted aquariums since the plant mass will take up the red. 6300k lighting starts to have more of a red tint. It’s not very popular since algae grows from the red.
With bulb lighting, it’s different. Unlike leds, you can put two or even four different bulbs with kelvins together to mix the lighting.
Kelvins only measures the color temperature of the light. PAR measures the light intensity. It stands for “photosynthetically active radiation.” This form of measurement wasn’t found too long ago so not all people use PAR. Before PAR, people measured their light intensity by wattage per gallon. Thanks to “Hoppy” from the Planted Tank Forum, he proved wattage per gallon wrong and introduced PAR. Read his post about it here. PAR is more important for planted aquarium owners than the other types of aquariums. Their are two types of planted tanks, low tech and high tech. Low tech is for people that don’t want to use pressurized co2 and may or may not dose fertilizers. High tech is for people that use pressurized co2 and dose fertilizers. Learn more here. Usually, PAR values between 15 to 30 is low light for low tech aquariums. Values between 30 and 70 are in between. Values between 70 and 120 is high light for high tech aquariums. Light intensities also vary by the height of your tank.PAR values of the Finnex Ray 2 Led
The picture above is a graph of the PAR values of a led lighting system. The left side of the graph resembles the depth of the aquarium in inches while the bottom of graph resembles the distance from the led to the surface of the water in inches. As you see in the graph, the deeper the aquarium gets, the less PAR. Also, the higher the led is from the surface, the less PAR. That’s why having a deeper aquarium requires stronger lighting.
PAR and kelvins are measurements to help our aquarium but lumens is different. Lumens measures how bright the light is to the human eye. The higher the lumens, the more brighter it looks. Lumens isn’t as important as PAR and kelvins, but something to keep in mind of. Lumens doesn’t change the amount of light going into the aquarium, only the amount of brightness you see in your eyes.
There’s many different kinds of lights you can buy for your aquarium but you don’t know what to choose. Some lights are outdated such as metal halide which isn’t a very good lighting source anymore as there are much better ones. The two best lighting sources there is is florescent bulbs and leds
Florescent bulbs are long pole shaped bulbs that stretch across your aquarium to light it up. This lighting has been used for a long time and hasn’t changed much. The bulbs itself are pretty cheap but with that you have to add the reflectors. The reflectors reflect the back part of light that isn’t facing the aquarium back to the aquarium. You also have to add the fixture to hold everything together which can be sometimes expensive. The bulbs also have to be changed every 6 months since they burn out fast. Not only do the bulbs have to be changed, but the each bulbs can make 50 watts! That’s not good for the energy bill. But the good thing about bulbs is you can customize more. For example, you can put one 6500k bulb and a 10000k bulb together to make a different look. You can customize your bulbs any way you want. The bulbs aren’t all one size. There’s different types of bulbs with different PAR ratings and sizes. Some popular sizes include t5ho being the strongest, t8, and t12 fixtures. The graph below will help identify the intensity of the bulbs:
Led lights started not too long ago. Some people just prefer the bulbs over the led but led’s are slowly getting better and better. Unlike bulbs, these last very long, up to 10 years. Wattage is also low ranging from 20 to 100. The bad news is these fixtures can be pretty expensive. Some led’s even have customization like moon lights, changing colors, and changing intensity. Some good brands of leds on the market right now are Finnex, Current Usa, Kessil, Marineland, Beamswork, and more. You can also make your own DIY led but good skill in this is required. The led fixture contains many single leds which have different or same kelvins. Red or blue leds can also be added for better plant growth and customization.
So, you see how much lighting is complicated. Knowing this can help you succeed in the aqua hobby without trouble.