In a planted aquarium, the light does far more than let you see your fish. It powers photosynthesis, decides how well your plants grow, and changes how the colours of plants and fish look. Choosing the wrong light is one of the most common reasons a planted tank struggles with slow growth or algae.
What does WRGB mean?
WRGB stands for White, Red, Green and Blue, the four LED colours in the light.
- White provides the main, natural-looking illumination.
- Red supports plant growth and brings out the red tones in plants such as Rotala and Ludwigia, and in fish like cardinal tetras.
- Blue is also used by plants and gives the water a clear, deep look.
- Green balances the spectrum so the tank looks natural rather than pink or purple.
A plain white LED can grow plants, but a WRGB light gives you better colour and a fuller spectrum for growth.
Colour temperature: why 8000 K
Colour temperature, measured in Kelvin (K), describes how warm or cool white light looks. Lower values look yellowish, and higher values look bluish.
Around 8000 K is a popular choice for planted tanks because it looks crisp and bright, makes greens look vivid, and still contains plenty of the red and blue light plants use. Both BTREE aquarium lights are WRGB with an 8000 K colour temperature.
Match the light to your tank
The most important rule is to choose a light that covers the full length of your tank, so plants at the ends are not left in shade.
| Tank length | Recommended light | Fixture size |
|---|---|---|
| 2 to 2.5 feet | BTREE 60 W WRGB light | 57 × 15 × 2.5 cm |
| 3 to 3.5 feet | BTREE 90 W WRGB light | 87 × 15 × 2.5 cm |
Each light suits tanks up to about 1.5 feet wide and 1.5 feet deep. For deeper tanks, light reaching the bottom is weaker, so choose plants that grow well in lower light at the base.
Features that matter
- A dimmer: lets you start lower when setting up a new tank, and increase brightness as plants settle. This is one of the simplest ways to avoid algae.
- An aluminium heatsink: LEDs last longer when they stay cool. A full aluminium body carries heat away from the LEDs.
- A slim, light fixture: easier to mount and looks tidy above the tank.
- Warranty on the LEDs: BTREE aquarium lights come with a 2-year warranty on the LEDs.
How long to keep the light on
More light is not always better. If plants get more light than they can use, algae takes advantage of the extra.
- Start with 6 to 8 hours a day, and use a simple plug-in timer so it is the same every day.
- In a new tank, use a lower dimmer setting for the first few weeks.
- If you see algae, reduce the hours or brightness before adding chemicals.
- Balance light with CO₂ and fertiliser. Strong light without enough nutrients usually leads to algae.
Quick checklist
- Measure your tank length and choose the light that covers it fully.
- Choose WRGB for better plant colour and growth.
- Use a timer and start with 6 to 8 hours.
- Use the dimmer to find the right brightness for your plants.
Both lights are made in India and available in the BTREE Shop with free shipping. Aquarium shops and installers can contact us for bulk pricing.