Height of lights

[schlitz]

I have a 90 gallon reef tank and I just purchased two lights to hang on brackets above the tank. I am struggling with shadows (especially by the overflow box). Am I better to put the lights higher or lower? Further apart or closer together? I keep trying different things but haven't been pleased with any of the results.

 

[MichaelReefer]

That question is hard to answer. What are the dimensions of the tank? The light? Do you have any Par numbers?

I would personally recommend renting a par meter and mess with them until you get it how you like it.

 

[vetteguy53081]

Depending on type of coral, happy medium is 8-10” above water line

 

[schlitz]

Any ideas on eliminating (or reducing) shadows?
What is a par meter?

 

[PatW]

A par meter measures the intensity of the light in the photosynthetic spectrum (mainly blue). Corals vary on how much par they like. Acropora like about 350 and a bit higher. LPS corals go far lower and most soft corals are not photosynthetic so you only need enough light to see them. Par meters can be pricy but you can rent them to check your light levels.