a better alternative is fine beach sand...but u must include resin in your filter system to counter water hardness. what u are using now is too big to go into their mouths, although river sand could be use, there is the danger of it getting stuck in their gills.....this is something u should consider.
btw i notice u are using top box filter...actually its risky since box filters are craps ...and im sure u dun wan to lose your fish due to nitrite buildup, believe me Geos are quite sensitive. notice the dark horizontal and vertical bars on their bodies...it shouldnt be there at all...its a sign and a warning.
this is the fine beach sand
with the right water condition geos will not show any dark bars.
no bars
