Help / Opinion please on return pump flow range and GPH

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XLReefer525

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Opinions please! Forget about head loss for the moment and please help me understand this. I have a Sicce Syncra SDC 7.0 return pump which is a DC adjustable pump with an advertised flow range of 800-1900 GPH. If I run this pump at 50%, am I running 950 GPH (1900 highest speed x 50%), or am I running 550 GPH (1900 highest speed minus 800 lowest speed = 1100 x 50%). If it's the first one, then that would be higher than the advertised lowest GPH. Anyone??
 
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blaxsun

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950Gph. If you run it @10% it’s approximately 190Gph, minus vertical height, elbows, etc. If you go to Sicce’s website and look up the SDC pumps they have performance charts that show what the maximum output in Gph will be based on head loss.
 

Montiman

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I think you are way over thinking this.

If this is a return pump I would just plug in the pump and run it at max power. if your drains can't handle it then you over bought the pump. I don't want a pump with a "flood my tank" setting.

The exact GPH has virtually no relevance except for with a UV sterilizer. If you are trying to dial the flow for a UV don't overthink that either. In most cases a return pump at max flow is just about right for a UV algae kill rate but you will need a lower flow for parasite control.
 

nereefpat

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I seriously doubt that the ratio between the control % and gph is exactly linear.

I would guess your second option is closer to correct, but then a DC pump with head pressure will be nowhere near that high.

I agree with just running the pump, and finding a flow that you like through the sump that your overflow can safely and quietly handle.
 
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XLReefer525

XLReefer525

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Thanks for the replies and again, ignore head loss for a moment. What I asked about running at 50% was just an example. I'd really like to know what the answer is. I sent an email to Sicce but have not heard back. I mean why have 800 GPH as the lowest end of the flow range if it can go down to almost zero?
 
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Opinions please! Forget about head loss for the moment and please help me understand this. I have a Sicce Syncra SDC 7.0 return pump which is a DC adjustable pump with an advertised flow range of 800-1900 GPH. If I run this pump at 50%, am I running 950 GPH (1900 highest speed x 50%), or am I running 550 GPH (1900 highest speed minus 800 lowest speed = 1100 x 50%). If it's the first one, then that would be higher than the advertised lowest GPH. Anyone??
If it's easy, put the return pump hose into a 5 gallon bucket and see how long it takes to fill. If it takes a minute, 300 gph. If it takes 30 seconds, 600 gph.
Approximate the actual height if possible.
 

KStatefan

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Thanks for the replies and again, ignore head loss for a moment. What I asked about running at 50% was just an example. I'd really like to know what the answer is. I sent an email to Sicce but have not heard back. I mean why have 800 GPH as the lowest end of the flow range if it can go down to almost zero?

800 gph is the flow at zero head at the minimum speed.
 

blaxsun

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800 gph is the flow at zero head at the minimum speed.
The minimum speed is 1-3%, and I guarantee it’s not 800Gph. I have the SDC 6.0 and 9.0 and you can run them at a trickle if you choose to (useful when feeding).

There are reasons and scenarios where you may not want to run a pump @100%, ie: where the return flow is sandblasting your corals, turning the tank into a snow globe or causing your fish to flee for their lives.
 

outhouse

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im running my DC pump at 45% to save wattage and have quiet flow. anything over 700 is way too much for a return pump. Run as low as you want and keep your AC bill down, and have a quiet tank. 1000gph would be ridiculous
 

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im running my DC pump at 45% to save wattage and have quiet flow. anything over 700 is way too much for a return pump. Run as low as you want and keep your AC bill down, and have a quiet tank. 1000gph would be ridiculous
My Sicce 9.0 delivers around 750-800Gph @45% rated @2500Gph), but this is on a 200-gallon system (160-gallon display). So that’s on the higher end of the 3-5x hourly tank turnover.
 
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outhouse

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My Sicce 9.0 delivers around 750-800Gph @45% rated @2500Gph), but this is on a 200-gallon system (160-gallon display). So that’s on the higher end of the 3-5x hourly tank turnover.
My Jebao 10000 is almost an identical flow pump, and lol im running it just like you at that same exact rate, I have a 210g tank and a basement 100g sump so maybe 270 actual water volume. Its nice having a quiet tank. More then enough for a skimmer and a heater and ATO and kalk/ ca reactors
 

outhouse

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So in a perfect world you would get 950 at 50%. but besides head height you also have tube or pipe diameter that can reduce flow. In the real world your not going to get 950gph at 50% with that small of a pump. I ran as much 1 1/4 pvc as I could. and ran a T with 1" on either side and made a Y instead of a T to run my 2 outputs, which go down to 3/4 through the tank. It takes a few tricks to keep flow at its highest ratings
 

workhz

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When I spoke with the tunze rep, he specifically stated that the control was more linear between 30-70%. The stuff at the bottom end and top end were all over the place.

I’m pretty sure that math for 50% is the middle of the range. So if it says 500-1000gph, 50% would be 750.

Whoever said you can slow it down to a trickle, was that level with the pump or going up a few feet?
 

blaxsun

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When I spoke with the tunze rep, he specifically stated that the control was more linear between 30-70%. The stuff at the bottom end and top end were all over the place.

I’m pretty sure that math for 50% is the middle of the range. So if it says 500-1000gph, 50% would be 750.

Whoever said you can slow it down to a trickle, was that level with the pump or going up a few feet?
That could very well be - I’ve never measured it. When my Sicce SDC 9.0 drops to 5%, it’s barely enough to keep water flowing into the overflow (the water level in the display drops quite a bit).

In any event, if one is really obsessed with the flow rate something like Neptune’s flow sensor is probably the way to go. At the end of the day (speaking only for my tank) I really don’t care. I have an approximate idea, the fish and corals are happy and I’m not dumping a cup of substrate out of my sock filters every week.
 

KStatefan

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The minimum speed is 1-3%, and I guarantee it’s not 800Gph. I have the SDC 6.0 and 9.0 and you can run them at a trickle if you choose to (useful when feeding).

There are reasons and scenarios where you may not want to run a pump @100%, ie: where the return flow is sandblasting your corals, turning the tank into a snow globe or causing your fish to flee for their lives.

I miss understood the specs then I do not have one yet.

1631959320420.png


I read this chart to mean that at the min wattage 20 the the max flow a 0 head was 800 and the max head height was 6.5 ft.
 
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