Help sizing return pumps please.

[Weasel1960]

I am designing my system and could use some help with determining head loss for my return pump selections. I am planning a 90 gallon DT. At 5X the volume that is 450 GPH.

Here is what I would like to do.

1. Trying to cut some up front costs so will be buying Jebao pumps and replacing as I progress in the hobby. I will be selecting DC pumps to give me some flexibility in flow.
2. Want redundant pumps. Pump #1 will pump straight back to the DT from the sump. Pump #2 will pump through a manifold that will have a UV Filter and a combination Carbon/GFO Reactor on it, then will go back to the DT.
3. I understand the general principals of head loss on a pump. I estimate P1 will have about 5’ vertical, 2’ horizontal and 3 elbows for a total of about 8.2 feet.
4. For P2 I am estimating about 10 feet of loss for the additional piping and elbows. What I don’t know how to figure is loss through the UV and the Reactor, and through any flow monitoring device but how do I determine this if those specs are not provided in the sales information?
5. The new Jebao MDP series does not have any published performance charts that I can find but the sales info does provide max flow and head height. Am I correct that If the info says max 924 GPH that it is at the pump and that at a max head of 11.5 feet flow will be nearly zero? How do I figure out my in between values? Can I do it through a proportional loss? IE: 924GPH / 11.5 feet = 80.3 GPH/foot, so my 10 foot of head would only be pumping (11.5-10)*80.3=120.5 GPH? I realize this is a straight line graph opposed to a true performance chart which is a curve.

Not sure if I am over thinking this or not. Have other questions but will start with this to get a better understanding first. Thanks in advance.

 

[blaxsun]

Run the UV off your main pump/return and assign the second pump for just the manifold.

 

[Weasel1960]

Run the UV off your main pump/return and assign the second pump for just the manifold.

For knowledge why? And still leaves the question of head loss through the UV. Or is the UV just counted as pipe in the horizontal or vertical position?

 

[blaxsun]

For knowledge why? And still leaves the question of head loss through the UV. Or is the UV just counted as pipe in the horizontal or vertical position?

Because you need a predetermined flow rate through the UV in order for it to be effective. Well, you'll need to count any 90-degree turns on the UV as well.

 

[DCR]

You can roughly assume a straight line between max head and zero head flow rates (at 100%) for a Jebao.

 

[Weasel1960]

Because you need a predetermined flow rate through the UV in order for it to be effective. Well, you'll need to count any 90-degree turns on the UV as well.

Good thought on the turns. Yes I know there is a predetermined rate depending on running for bugs or algae. Hence the idea of adding a flow meter so I can dial up the DC pump as needed.

 

[Weasel1960]

You can roughly assume a straight line between max head and zero head flow rates (at 100%) for a Jebao.

I was just looking at the Ecotech S2 chart and it is very similar in size to my example. To me it seems like I will be loosing a lot of head for not having very much piping.

Vectra – EcoTech Marine

ecotechmarine.com

 

[DCR]

I was just looking at the Ecotech S2 chart and it is very similar in size to my example. To me it seems like I will be loosing a lot of head for not having very much piping.

Vectra – EcoTech Marine

ecotechmarine.com

Depends a lot on your pipe size. I suspect you are using 3/4". The S2 with 1" will easily get you there on the main circuit. Flowing through a UV and flow meter is going to significantly reduce the flow on the second circuit.

 

[Weasel1960]

Depends a lot on your pipe size. I suspect you are using 3/4". The S2 with 1" will easily get you there on the main circuit. Flowing through a UV and flow meter is going to significantly reduce the flow on the second circuit.

Thanks for info, not honing in on a particular model yet just trying to fully understand what needs to be accounted for and how.

 

[Weasel1960]

As another question…when a DC pump gives a min/max flow rating (example, 100/1000), I am assuming again that is straight out of the pump at max power or minimum power? If so then flow on min power will also be reduced by head BUT could be compensated for by dialing it up?

 

[DCR]

As another question…when a DC pump gives a min/max flow rating (example, 100/1000), I am assuming again that is straight out of the pump at max power or minimum power? If so then flow on min power will also be reduced by head BUT could be compensated for by dialing it up?

The max head and max flow points are always at 100% power (speed).

 

[becon776]

Are there any internal pumps besides abyzz ($$$ = ) that handle head pressure better than others? Unfortunately I am stuck with 3/4" plumbing on the rs reefer. Smaller diameter plumbing / 90° elbow etc... all equate to increased head. Looking ti get more turnover into sump.