how ever far you wish. i actually have my plazma just a few inches away from mine. i have a very small room. doesnt help having two 55 gal aquarium n stands in there. just make sure all the wires and any filter hoses have a drip loop in them. i also installed a special outlet that is used for all my aquarium power supplies. it trips a breaker inside that trips if water gets in it. its code for many states to have these near water. ie sinks, bath tubs, and such. i did i just to be safe.