*snip*
To reduce that effect, fill the tank as high as possible. The
additional water will prevent the water from falling as far, thus
reducing the turbulence and the splatter noise.

Just a word of caution some tanks (like mine) will leak towards the
very top where the plastic edge meets the glass I had that happen and
it started a syphon and a little stream of water started running down
the corner of the tank and(it made a mess before I noticed even though
it was quite slow) it wouldnt stop till I broke the syhpon by taking
the water level down past the plastic edge...