My first impression of having a glass sand bed is the whiteness of the sand and sparkles under good lighting. My idea of having a sparkling white sand bed.
Glass beads have several advantages over regular coral sand.
Glass beads being inert would not break down and is chemically inactive. It also would not absorb phosphate or any other heavy metals which is the primary concern of DSB users in US.
It is also much heavier than coralsand thus settle within hours after washing. I wouldnt be concerned about surface area as these glass beads are much finer than C0 sand with a size of 0.15mm to 0.09mm.
DSB height can be reduced due to the fine size and mud texture of the glass beads.
I used the ballotini impact spheres manufactured by Potters Industries Inc in Austrialia.
Typical Properties:
Shape - spherical
Color - clear
Hardness (Knoop) - 515
Compressive strength - 36,000 psi (avg.)
Density - 2.5 g/cc
Specific Gravity - 2.45-2.50
Free silica content - 0%
I used 2 sizes for my sand bed.
Size 10, US Sieve 100-170, micron 150-90, roundness 90%
Size 3, US Sieve 20-30, micron 850-600, roundness 65%
Full Specs can be found
here
The Size 10 glass beads are so fine that it pours like liquid and have a mud texture when wet. There are no risk of cuts from the glass beads as they are too fine to even scratch yr skin.