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			#1  
			
			
			
			
			
		 
		
		
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			 I have tryed two of them using same numbers and get diff answers  
		
	
		
		
		
		
		
	
		
		
	
	
	I use 6 ft for length and a mag9 pump as my example no unions or valves yet. I get 7.16 head pressure and flow rate of 635 gph at reefshow site and at reef centrel site i get 7.84 head pres. and 587 gph so I was told i need about 10X tank cir per hr.for good flow so i would need 720 correct for a 72 gal tank could someone tell me if this is correct or what i do need other than more reserchand experience if i use a mag 18 is that to much flow or should i use like a mag 12 or rio 20hf.to get the right numbers  | 
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			#2  
			
			
			
			
			
		 
		
		
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			 i have a mag 12 on my 105g, plus a 270gph powerhead 
		
	
		
		
		
		
		
	
		
		
	
	
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			#3  
			
			
			
			
			
		 
		
		
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			 What are you keeping or planing to keep? SPS you can and should have way more flow. 
		
	
		
		
		
		
		
	
		
		
	
	
	Dave  | 
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			#4  
			
			
			
			
			
		 
		
		
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			 Quote: 
	
 Steve 
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	 *everything said above is just my opinion, and may or may not reflect the views of this BBS, its Operators, and its Members. If cornered on any “opinion” I post I will totally deny having ever said this in a Court of Law…Unless I am the right one*Some strive to be perfect.... I just strive.  | 
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			#5  
			
			
			
			
			
		 
		
		
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			 I use a Mag 12 for a return on my 60 gal. with slightly more head loss than you are calculating with.  I also have 2 Aquaglobe mini powerheads pushing  300gph each.  Corals and fish are all very happy  
		
	
		
		
		
		
			I would probably go with a Mag 12 or even an 18 on your 72 depending on how many return outlets you want from the pump. HTH 
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	Scott __________________________________ The beginning of knowledge is knowing you know nothing  | 
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			#6  
			
			
			
			
			
		 
		
		
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			 I'm not an expert , but from what I've read and have been told from various people, you only need to have your tank cycle about 5-7 times per hour to ensure good water quality. If your water is moving through your sump too fast it may not get proper contact time with the skimmer , heater and whatever else you may have to filter or scrub etc. It realy depends on what type of tank you are setting up. I personally can't see why 10 times would hurt but you may be just wasting your money when the pump you have now would be fine . Maybe somone will post a more accurate statement. HTH 
		
	
		
		
		
		
			Cheers 
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	I bent My Wookie  | 
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			#7  
			
			
			
			
			
		 
		
		
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			 The amount of flow sometimes is not as important as even flow ... what I mean is you can get 5 to 10 times water turnover per hour through your sump if you like ( although 3 to 4 times  per hour would probably suffice ) ... but more importantly is to get circulation throughout the tank ( either with extra powerheads or closed loops ) and avoid " dead spots " where detritus can accumulate unnoticed ... I think this is the problem area we run into that causes water quality issues. 
		
	
		
		
		
		
			So the bottom line is if you have SPS ... get 3 to 4 times per hour through the sump ( any more than that and you may run into overflow not being able to handle the volume and more contact time for skimmers / heaters etc ) And then another 7 or more times per hour from closed loops or powerheads HTH 
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	Steve “The most important decision you make is to be in a good mood.” ― Voltaire  |