I just did a 10 gal water change - it's 55 gal tank. We also had added 3 pecies of live rock. When I did the water change - i did cleaned the sand/CC and moved a good bit of sand around when we added the live rock. After a few hours the tank started smelling really bad - like rotten eggs. Before the water change the water smelled fine. We used distelled water bought from walmart. After we noticed the smell we removed the 3 new peices of live rock and placed them in the sick tank. However the rock didnt smell that bad. What could be the cause - rock - or stirring up the sand/CC? Please help my whole house smells!