Just got a 55g tank NEED HELP

[Stalk3r]

the tank is cycling and now i want to put sand in( I know i should have put it before i put the water in ) but is it ok if i put sand in and anyone know where i can get black sand for cheap?? any decor ideas? (cheap) the tank ran my pockets

Ps- im going to house a RD, GT and a JD juvies

 

[Paper Chasin]

careful if you are adding sand to a full tank with filters on. sand can cause problems to some types of filters if particles get into the propeller.