Is my guinea pig cage okay?

Is it okay to put my guinea pig in a dog crate? It has a removeable litter tray at the bottom (where I put bedding.) And is basically like a regular cage. I don't have the room for a HUGE cage so I thought this cage would be okay. The size is 30.0 x 21.0 x 24.0. And I put in a loft at the top of the cage. And his way of reaching the loft is a drainage pipe. Is this an okay home?