I;ve only used silica sand in a FW
tank, so I can't really comment on SW
silica personal experience.
here's a sum-up of what I consider to be "the facts"
Silica is not
bad for your tank. It will NOT release silicates as some say, they are two different things.
Silica, on a microscopic level has sharp edges. These sharp edges deter some mico-fauna from growing in your DSB
, thus limiting sand bad bio-diversity.
Silica sand provides no Ph buffer capacity. Again, this is not
bad, it is simply neutral.
Argonite sand is good for your tank
On a microscopic level there are no edges but each grain is actualy a small rounded ball.
Argonite Sand is Calcium Carbonate based and provides for Ph buffering of your water.
so either sand "will do" but you are of course better off
with argonite sand.
it's up to you if you wand to pay the extra. Of course... if you want... buy few bags of CC
and find a way to break it down into sand, like a giant rock tumbler. Thats all argonite sand (and the reef floor in general) is... CC
thats thats washed back and forth billions of times and worn small and smooth.