Selecting the appropriate aquarium lighting can be a tricky job. However, if you understand how lighting impacts your aquarium, you’ll make the right choice.
Why is aquarium lighting important?
For starters, aquarium lighting has an aesthetic purpose. It helps illuminate the aquarium and brings out the colors of your fish.
If you want to grow plants or maintain a reef aquarium, lighting is absolutely necessary. Plants transform light into energy through the process of photosynthesis. To top it off, different plant species require different levels of light; certain plants can thrive in near-complete darkness (Like Anubias Nana), while others, like Hemianthus callitrichoides ‘Cuba’ require extremely powerful lighting to survive.
Without enough light – your plants will wither and die. Too much light can greatly heat up your aquarium, and cause certain plants to sprout out of control.
Almost any aquarium shop should be able to offer advice on lighting based on the size of your tank and the plants you’ve bought.
Aquarium lighting evaluation factors
- Kelvin rating – this refers to the color spectrum of lighting. It can range from high to low, resulting in “cooler” or “warmer” colours. If you’d like your aquarium to have a warm, yellow-ish tint, you’d usually want lighting with a lower Kelvin rating (about 2700K). For a pure-white natural daylight effect, 6500K is the norm.
- Lumen rating – the brightness factor of lighting, as perceived by the human eye. It’s the measurement of visible light. The higher the lumen rating, the greater the light’s intensity.
- PAR rating – short for Photosyntetically Active Radiation, this represents the amount of light that goes through water and which plants, corals or algae use for photosynthesis.
- Wattage rating – it refers to the the amount of electrical power used and it’s expressed in watts.
Types of aquarium lighting
There are various kinds of lighting, based on the different types of light bulbs and effects you want for your aquarium:
- Color-enhancing lights – this type of lighting enhances the colors of aquarium inhabitants.
- Fluorescent lights – this lighting is perhaps the most common and inexpensive type out there. Fluorescent bulbs don’t look like standard bulbs, instead they’re circular tubes. They come in different sizes, which enables them to fit in any aquarium.
- LED lights – they’re long-lasting and powerful. They aren’t actual bulbs, but diodes that produce light, hence the name Light Emitting Diodes. When you switch them on, they enhance your aquarium’s appearance by giving it a shimmering effect. You can choose from a vast array of sizes, colors, effects.
- Incandescent lights – this type of lighting works by using electricity to heat a bulb’s filament wire. The result is the light which the wire produces when it starts to glow.
- Full spectrum lights – full spectrum bulbs are also known as daylight bulbs. This is because the light that they give off is similar to daylight.
- Actinic lights – since actinic bulbs emit blue light, this penetrates deep water more efficiently than standard white light. If you’re the owner of a saltwater aquarium, this type of lighting system will be ideal.
Selecting the right kind of lighting for different aquariums
Before buying, you need to figure out which aquarium you plan to keep. Do you want a freshwater or saltwater aquarium? If you opt for a freshwater aquarium, do you want a planted aquarium or are you planning to keep only fish?
Another crucial factor to keep in mind before choosing aquarium lighting is the size of your fish tank. Deeper fish tanks require more light – as light gets weaker with each inch of water it has to penetrate.
Tip: The more light your aquarium needs, the hotter it’ll get. Certain lighting systems might require additional aquarium equipment like a fan or water chiller. They prevent your aquarium from overheating.
How much lighting do fish-only aquariums need?
Technically, you can run a fish-only aquarium on daylight alone. As opposed to plants, fish don’t depend on light to survive. Some species will even be stressed by light. In this case, lighting is only necessary for the sake of aesthetics.
Aquarium lighting for planted aquariums
However, if you want a planted aquarium, you’ll need between lighting with 2 and 5 watts per gallon. For example, a 20 gallon aquarium would require multiple bulbs with a combined power of at least 40 watts – and that’s assuming you’re keeping non-demanding plants. Before you opt for any lighting system, know the measurements of your aquarium, as different types of lighting systems provide different intensity and wattages of light.
Depending on the plants you have, the amount of light that’s considered optimal for them varies. If we classify plants into difficult, medium and easy based on their need of light, these are the general rules to follow:
- Difficult plants – 40+ lumens per liter. (1 watt per liter)
- Medium plants – 20-40 lumens per liter. (0.5 to 1 watt per liter)
- Easy plants – 10-20 lumens per liter. (0.25 to 0.5 watts per liter)
Usage of aquarium lighting
Don’t keep the aquarium lighting on for longer than 8 hours per day. Just like in nature, sunlight isn’t provided for a full 24 hours, so make it your goal to mimic natural conditions for both your plants and your fish. Despite the benefits of light, if its presence is excessive, it can lead to algae growth in your aquarium – or cause stress in your fish.