glass and light

        Someone asked about glass between there tank and light source.
Well glass is a natural UV filter.  This can be good or bad depending upon
the amount of UV light your bulbs are putting out.
        Generally a better substatute is plexeglass.  Plexeglass alows UV
light to flow through it much more freely.  And thickness is not an issue
either with plexeglass.  Remember though it is not as rigid as glass tharefore
it either needs support all the way around or a much thicker piece than 
windoe glass.