those aren't the only elements and trace minerals that our critters use

 .....stuff like strontium, potassium, iodine and a host of others will slowly get used up.....if your not adding these things and not doing regular water changes, then these minerals and elements will never be replenished....
 
		
	
		
		
		
		
			
				__________________
				260g mixed reef, 105g sump, water blaster 7000 return, Bubble King SM 300 skimmer, Aqua Controller Jr, 4 radions, 3 Tunze 6055s,1 tunze 6065,  2 Vortech MP40s, Vortech MP20, Tunze ATO, GHL SA2 doser, 2 TLF reactors (1 carbon, 1 rowa). 
http://www.canreef.com/vbulletin/showthread.php?t=50034 . Tank Video here 
http://www.vimeo.com/2304609 and here 
http://www.vimeo.com/16591694