Using a few well placed rocks and pebbles would allow the available sand to
be spread over a smaller area, ie around those items of decor. This would
allow for greater depth of sand which is essential so as not to expose the
roots of any plants in your tank. Only use rocks bought in aquarium shops,
don't be tempted to use ones found in gardens or on beaches etc. They may
well be contaminated with unseen polutants!