To successfully grow live plants in an aquarium, one of the first necessities is providing light for the plants.
Light sources
It is important where the aquarium is positioned when you are lighting it. Ideally you want to be able to control the light completely so a dark area away from the window is best. Sunlight on the tank can cause algae blooms and also tempreture fluctuations.
There are a few types of lights that are suitable – I am only going to mention fluorescent as they are generally the cheapest and easiest to get, run and maintain. Fluorescent lights are also suitable for almost all aquariums.
The type of tube you use is very important. You want to simulate natural sun light so it is best steer away from all the fancy colours available and go for a full spectrum light (not a broad spectrum). Many of the ”aquarium lights’ are not ideal for plant growth as the manufacturers have concentrated on bringing out the the fishes natural colours and not not plant growth.
The bulbs I use can be purchased at most hardware stores for a third of the price that is asked by most LFS. 6500k is a good choice, which is commonly labelled as Bright daylight. Growlux is another type which I recommend.
How much
A reasonable rule of thumb is about ONE Watt per LITRE of aquarium water. There are many varying opinions here but one needs to also remember that different plants need different conditions eg. Anubias sp. need less light than Echinodorus sp. to thrive.
It is very difficult to overdo the amount of lights and I feel its a good idea to jam as many tubes under the hood as you can afford (within reason).
Duration
Most aquarium plants are from the tropics where there are equal day and night lengths. Many Aquarists try and copy this. I find I get better results with less algae when the lights are on for no more than 10 hours a day.Although many flowering plants can be induced to flower by gradually increasing the photo period by an hour or so.
A timer is a big help with this.They are available from most hardware and department stores, for usually only $5- $20. Try and time the aquariums day period when you are most likely to be there so you aren’t tempted to turn on the lights at the wrong time
