jflowers
Ignore my post count, it means I waffle too much,
Eventually, the grains may wear the impeller, but thats a long way off and sand will be much better for your fish. Good external filters should never be effected as the sand grains will be filtered out before they reach the impellar chamber. I have used sand for more than two years on an internal filter though, without problems.
Jon
				
			Jon
 
	             
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		