I just changed the substrate in my tank from whiteish gravel to sand ( I believe it is silica sand, it was labeled as landscaping sand but the consistency looks like silica). I use to vacuum my gravel once a week with my python hose. What I want to know is what is the best way to keep the sand clean? Can it be vacuumed like the gravel? If so does anyone have any tips for doing it? Also, I have some holey rock and large river rocks dispersed throughout. Do I need to remove the rocks periodically to clean under them? If so, how often? THANKS IN ADVANCE!!!!!!