Planted Tank Lighting
Written by Hector Ortiz   

Light energy is an essential ingredient to making a planted aquarium lush and green. It drives photosynthesis and the plant’s ability to consume nutrients from the water column. Without adequate light, plants won’t be able to grow properly.Planted aquariums require  eight to ten hours of light, on average, to allow plants to metabolize the energy and complete their photosynthesis cycle.

 

The general rule of thumb for aquatic plants is that each tank needs at least 2.0 watts per gallon (wpg) in tanks that are greater than 20 gallons. Smaller tanks will need a little more wattage. For the beginning planted aquarist, I recommend you start with a lower wattage, i.e. around 2.0 wpg for eight to ten hours.  Once you begin to understand the nutrient balance and plant growth that’s the time where you can experiment with increasing lighting. However, most times staying within this photoperiod range is more then adequate for plant growth.

One of the best ways to avoid algae in a newly set up planted aquarium is to use  minimal lighting for the first few weeks.  By minimal lighting,  I mean reducing the photoperiod to seven to eight hours, and, if possible, switching off one of your bulbs in your lighting fixtures.  By doing this, you’ll give your newly planted plants time to adjust to your aquarium conditions. It’s like going out running for the first time. You wouldn’t want to start off on the track at full speed because you’ll know you’ll burn out after the first lap.  Instead you’ll do a warm up lap and gradually work yourself up to top speed. The same goes with aquatic plants. Give them a chance to adjust to the new conditions and they will thrive in the long run.

If you don’t do this, algae will flourish off the overdriven and dying plant matter that may result when there is too much light, not enough plants, and excessive nutrients (from the lack of healthy plants consuming it). Allow your plants to grow gradually with the conditions and you’ll find algae will have a hard time infecting your tank. 

Compact fluorescent lighting is the common main stay of aquarium lighting equipment.  It offers an efficient and affordable lighting solution for most planted aquariums.  T-5 High Output lamps are becoming more popular as the prices on the bulbs and its fixtures decline.  T-5 High Output bulbs burn brighter and more intense then regular Compact Fluorescents.  In deep aquariums (24 inches), T-5 High Output bulbs can penetrate deep into the water, where regular Compact Fluorescents could not. In a planted aquarium this aspect is very important when you’re trying to grow a compact foreground of Glossostigma elatinoides.  

Equipment aside, remember that in order to have a healthy planted aquarium you don’t need tons of light, but you do want to have enough for your plants to grow efficiently.

With High light comes great responsibility. Sound like a catchy phrase from a comic book movie?  Well, it’s true here, too. With more light (3.0+ wpg) you are essentially putting your plant’s metabolism into overdrive. Sure your plants may start growing faster initially, but without proportional high amounts of CO2 and fertilizers, this rapid growth will reach its ugly climax. So when in doubt, go with less light (around 2.0 wpg) and keep the fertilizers and C02 in adequate, small levels.  You’ll find the slower growth of the plants will make a much better aquascape than one you have to constantly trim to keep looking good.