T5 light modules have always been popular for hard corals aquarium with high SPS stock. Even one has to change the T5 lamps in every 12 months and the lamps have a high energy consumption, the T5-lamps have a lot of advantages: So high growth speeds and excellent colours are possible in hard corals; due to the vague light the death of corals is reduced because of self-shadowing effect. Even for beginners in the marine –aquaristic, T5 lighting is a good choice in order to directly prevent the errors which arises due to an incorrectly set lighting spectrum eg. When using LEDs. We have ATI and Giesemann T5 lamps which have been proven to be for a long term-use.