Lighting   Overtank suspension comes in two forms... those that fit inside the hood of an aquarium, and those that are free standing, allowing you to view into the aquarium from above (see diagram).  
     

More and more units are being made to fit this type of system. Many people who start out in the hobby with a lighting unit built into the hood buy this as an upgrade to their system. It allows you to completely replace the existing hood with a sleek metal/plastic unit.

One reasonf or this is that most basic aquariums come with T8 Lighting, and when upgrading to marine coral life this is insufficient. So Overtank systems were born. It looks fantastic and unlike the Halide Wire system there is no need to drill holes (however suspension for T5 systems are available) and it simply rests on the aqarium glass.

Access to the water is achieved by a pivot system where the whole lighting unit tips up.
 
     
         
   
As with the Wire suspension the main disadvantage of this is the aquarium isnt covered and fish can jump out the water, as well as increased evaporation from the surface. Water replacement will be a daily chore.
  
   
Set-up and maintenance is very easy, unlike those of wire where you need to get under the unit to replace the bulbs...