Return Pump Head Question

[Boochika]

I see a lot of folks posting here about their return pumps and aquarium sizes. I'm new to saltwater and coming along slowly here when it comes to pumps.

Oddly enough I'm an engineer but hydrostatics wasn't my strongest class, I have 3.66' of vertical lift in my planned setup and about 2 feet of horizontal piping. Also I have 3 elbows and 1 union ball valve and 1 check valve. When i put this into the calculator for a comparable pump to one I want to use it's only spitting out 5-8 feet of head pressure. I'm using 1" tubing.

If i do a hand calculation for this I get more than 10 feet of head pressure. This will cause me to pick dramatically different pumps. Right now I'm between the Reef Octopus Varios Series and the Sicce SDC and Sicce ADV series. If I can get it right I'd like to go AC because they seem to be more reliable, but I'm also interested in adjustability of the DC units.

Any help is appreciate here. I'm looking to have an 80 gallon tank with a 16 gallon sump with 7x flow (tank only, not including sump).

 

[RobZilla04]

Not an issue going DC IMHO. Lots running successfully here for a long time. Mine 2+ years. As an engineer I'm sure you are aware that going slightly oversized and running at less than 100% will extend the life & reduce heat.

 

[Boochika]

Would a Reef Octopus Varios 6 be overkill for the system I described? Could I use a Varios 4?

 

[RobZilla04]

Likely the 6 would be perfect, the 4 you would simply be running at higher percentage. Hopefully mcgyvr, or someone with better calculation skills when it comes to diameter selection will be around shortly to chime in.

FWIW I have a Jebao DCT-9000 rated at 2377GPH running at just over 50% plumbed at 3/4" and a length of 6ish feet and one 90 degree elbow. Whatever GPH that gets me, it's all my drain/sump can take. Increasing the % any higher and the sump water level drops due the drain limitations (single durso 1 1/2" overflow).

 

[Boochika]

OK so for example I used the red dragon 3 50W pump which is rated for roughly 1200 GPH and maximum head of 15 feet. And according to the calculator it's telling me I only have 6.2 feet of head pressure.

Why is my head pressure calculation so much greater when i do it by hand than the calculator? Is there an error in the calculator.

Also I have read that some of the DC pumps are not pressure-rated, what does this mean?

 

[Boochika]

Sorry here are calculator details:

Vertical length - 4'
Horizontal length - 2'
Pipe Diameter - 1"
Pump - Royal Exclusive 50w
90 Degree Elbows - 3
Ball Valves - 1
Union Couplings - 1
Check Valves - 1
Pipe exits -1
Entrances - 1

Total Losses at 6.2 feet of head, or 2.68 PSI with a flow rate of 797 GPH.

 

[Boochika]

Likely the 6 would be perfect, the 4 you would simply be running at higher percentage. Hopefully mcgyvr, or someone with better calculation skills when it comes to diameter selection will be around shortly to chime in.

FWIW I have a Jebao DCT-9000 rated at 2377GPH running at just over 50% plumbed at 3/4" and a length of 6ish feet and one 90 degree elbow. Whatever GPH that gets me, it's all my drain/sump can take. Increasing the % any higher and the sump water level drops due the drain limitations (single durso 1 1/2" overflow).

I did a quick calculation on this and at 100% it would be about 1400 gallons per hour so it seems you'd be at 700ish gallons per hour. Thanks.

I'm planning to do herbie overflow and hoping I can get more drainaig :hmm3::hmm3:

 

[RobZilla04]

I did a quick calculation on this and at 100% it would be about 1400 gallons per hour so it seems you'd be at 700ish gallons per hour. Thanks.

I'm planning to do herbie overflow and hoping I can get more drainaig :hmm3::hmm3:

Exactly the reason I went DC. There is no way the overflow and sump could handle that. Looks like I'm closer to 350-400 range so 5x turnover once you subtract rock volume.