I have hairgrass in sand and it does well. Dwarf hairgrass is more dependent on good lighting then the substrate it's planted in.

 

I have my glosso in lava sand. Does that count?

 

Not sure... what's lava sand? Is it doing well. Mine's pool filter sand.... anyone?

 

I've grown dwarf hairgrass in sandblasting grit, probably very much like pool filter sand, and it did well. With your set up it may try to take over the world.

 

Excellent... that's what I wanted to hear!

Thanks for the replies, people.

 

I have dwarf hairgrass grown on both sand and flourite sections of my low-light, no CO2 tank. Nothing's dying yet--but not growing very fast on either side.

I'll update when I upgrade the lighting and keep with no CO2.