i like the tank,and the guppies look nice. if you don't like the gravel,it's pretty easy to change. just put the fish in a bucket(or other not contaminated container that holds water),drain the tank,scoop out the gravel,put in new substrate(i like PFS),refill,add lots of prime,wait for temp to return to normal,done. *make sure to leave the filter the same. no changing cartridges. and make sure it stays wet in non chlorinated water so the bacteria stays alive
nearly a year of complete inactivity and still over 4 posts per day. dedication, eh?