Distance for MH Lights

no less than 6" to prevent water splashing up. if these are SE or without a splash guard (coralife makes DE bulbs with UV protection so you dont need a splashguard) and water hits them when they are hot, it is possible for them to burst. i have mine at 8
many people start around 12 for acclimation and lower them down to the desired height.
 
mine are about 9 inches from the tank since it's been up
 
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