Well dang... you just gave me my first good reason to not order live sand from the new and improved TBS. I've had that on my build list all along but you make a valid point. I have been using fiji pink and do not plan to use it again for the reason you stated. There really isn't a way to quantify the grain size of sand collected 12 miles below the Tampa Bay.The biggest thing I've done to help with scratches is to replace all my fine sand with caribsea special grade. The fine stuff gets in the water column and actually sticks to the acrylic and you won't notice until the mag starts scratching!
Is Special Grade ok for gobies?