Juwel Day-Lite Tubes have a Kelvin rating of 6500 and create a lovely bright daylight effect in your Juwel Aquarium. For best results combine one Day-Lite tube with a Colour-Lite or Warm-Lite to give a more natural colouring to your aquarium. Place the Day-Lite tube at the back to promote plant growth and use the Warm-Lite or Colour-Lite tubes to enhance fish colours. These tubes are T8 1\" thick fluorescent tubes and will fit all Juwel aquariums with existing T8 Light bars