Need help with first external pump purchase

[stevenp]

I'm looking for an external pump and have some questions. I want the pump to pull water from the display and down 3' to run it through a 1/10 hp Arctica chiller and back up to tank level, through a tee, then dispensed back into the display through two outlets. I would like the combined GPH from the two outlets to be just over 400 gph.

I've been doing some research on pumps and find that the higher end pumps don't even bat an eye at a 3' head. However, I'm not sure how much pressure will be lost through the chiller and plumbing.

The pumps I'm looking at are:

(1) PanWorld 40PX-MD20R External Water Pump - 480gph $109.95
(2) PanWorld 50PX-MD30R External Water Pump - 590gph $134.90
(3) Iwaki MD 20RLT - 420gph $159.95
(4) Iwaki MD20RLXT Water Pump - 540gph $169.95


Noise is a real concern of mine. I've read that the Iwaki's sound like an A-10, and the 50PX is quieter but nearly as quiet as the 40PX.

I'm leaning towards the 40PX.

I really need some advice here, I've never bought a pump before.

Steve

 

[this is me]

http://www.ereeftank.com/cart/catalog/Aqua_Medic_Ocean_Runner_2500_p_88.html

Cheaper than the ones you posted.
higher output.
only 38watts
the only draw back of this pump is that its big. about 6"x4"x4"

 

[JohnK]

If you draw water at the same height you pump it back then there is 0 head height. Otherwise it's only the difference between where the water is drawn and where it returns.

That said any plumbing will add effective head height depending on how much restriction there is.

I have a larger pan world pump and it is pretty quiet IMO.

 

[nunofs]

I'm not sure how much pressure will be lost through the chiller and plumbing.

I have a 1/4 HP Arctica chiller and it creates a huge amount of head loss... I can't tell you exacly how much, but it dropped my flow dramatically.

Noise is a real concern of mine.

I had a PanWorld 50PXX-MD30X (non-pressure rated) and it was pretty noisy, too noisy to be in my living room... there's a very loud humming sound because it's a fan-cooled pump. Ended up replacing it with a T4, now that's a quiet pump (but runs very hot, adds a few degrees to the water).

Not sure how the pressure-rated pumps compare, but if they're fan-cooled (I believe so), expect some noise... I realize tolerance to noise is a very personal thing, just don't expect a silent pump with the PanWorld.

Nuno

 

[stevenp]

Nuno,
Can you take a guess at what percentage of loss you have running it through the chiller?

Jimmy,
The pump will be on the floor, so it will be pulling water down 3' and pushing it back up 3'.

Steve

 

[mikestod]

I have a Little Giant 3-MDQ-SC that i don't use and am trying to sell. You're welcome to borrow it and try it out to see if it will work for you Steve. Here's the specs on it...

http://www.marinedepot.com/aquarium_pumps_little_giant_inline.asp?CartId=

The fan on it is fairly loud though, but you might want to try it to see if its the right flow...

 

[mikestod]

Steve,
Are you trying to suck water out of the tank, or are you draining water from an overflow or other source in the tank. If you are trying to draft with these pumps, you would need a self priming model. Otherwise you would break the siphon each time the pump turns off and have to manually prime the pump. Not only is this a PITA, if the pump shuts off from a power outage, you could potentially damage the chiller if you lose flow through it I'd imagine

 

[stevenp]

Sucking water out of the tank. Essentially a closed loop I guess you could say. I thought if both the inlet and outlet are always submerged, it should never lose prime?

Steve

 

[mikestod]

yes, thats fine, i wasn't sure if you were trying to use a U tube or something....that would be a different story.

 

[jacko]

I am selling a T3 for $120 :
http://www.bostonreefers.org/forums/showthread.php?t=12589

 

[stevenp]

Jacko,
800 gpm may be a little much. But, I'm still not sure what kind of loss in flow I'll see with a chiller.

Does anyone have an idea of how much loss there would be with a 1/10hp chiller? 20%? 50% 80% loss?

I'm just looking for a ballpark figure. I want to shed a couple power heads...

Steve

 

[JohnK]

"Jimmy,
The pump will be on the floor, so it will be pulling water down 3' and pushing it back up 3'."


"Sucking water out of the tank. Essentially a closed loop I guess you could say"

That's what I'm saying too, like in a closed loop there is no real head height because the inlet and outlet are at the same height. The weight of the water going up equals that of the water going down canceling out the backpressure.

That said, the plumbing and chiller will create back pressure or "effective head height".

My point is kind of irrelevant because it sounds like the "head loss" (which I would use intercangably with "effective head height") from the chiller will probablly be signifigant. All I was saying is that your talking about a closed loop as, as you said. Just don't add the 5 vertical feet into the equation.

I'm not helping since I can't offer any other advice on estimating what your head loss will be so I'll stop typing.

good luck
jk

 

[mikestod]

The correct term would be friction loss. Friction loss by itself is measured horizontially and based on pipe diameter, length, and construction materials, with variations for fitting, bends, fluid charecteristics. Vertical loss is a combination of head pressure loss plus friction loss. If you really want to get into it you can figure it out, but its beyond my mathematical skills....

Random link to the Hazen-Williams basic friction loss formula and calculator:
http://www.lmnoeng.com/hazenwilliams.htm

PS: Yes, I learned this 8 years ago to as part of my Fire Science degree, but I can't remember how to do it. As a mathematician or hydraulic enginerr for help instead of a firefighter. I just put the wet stuff on the red stuff!

 

[mikestod]

Steve, call the manufacturer and ask their engineering department for an estimate on friction loss between the input and discharge. You'll still have to factor in some head loss for gravity....

 

[nunofs]

Nuno, Can you take a guess at what percentage of loss you have running it through the chiller?

Best guess (just by looking at the amount of flow, namely with the outputs out of the water so that I could actually see how much water was flowing) is that my chiller decreased the flow from around 500gph to around 200gph... but don't think of this as a percentage of loss, I think it's more useful to account for the fact that there's around 300gph of loss. Also, my chiller is the 1/4HP, not sure if the 1/10HP would be the same in terms of head.

Nuno

 

[stevenp]

Wow, Nuno. I didn't think it would have been that much.

I'm taking Mike's advice on calling the manufacturer regarding head loss. I'll post what they have to say.

Steve

 

[nunofs]

Wow, Nuno. I didn't think it would have been that much.

Just read about a similar number in another thread (http://216.235.242.50/forums/showthread.php?t=12670) :

I installed my new 1/3HP Super Tradewinds chiller (...) it reduced my overall flow by 300-400 GPH

Nuno

 

[aweeks95]

hey steve any luck with the chiller yet? how about your mag5.....did you think about using that? it can be used as an external pump can't it?
if you don't want to use it are you thinking about selling it yet? if so let me know....
good luck with the chiller....
ANDY

 

[aweeks95]

where did you find the chiller? new or used?

ANDY

 

[stevenp]

Andy,
The chiller arrives tomorrow. I've been getting all the plumbing ready and rearranging the tank accordingly. It's a used 1/10 hp Arctica I bought from a Florida reefer that posted it on RC.

I won't be using the Mag. It's a Mag 2 and not a Mag 5 like I thought it was.

I'm looking at Iwaki and Panworld pumps, somewhere in the 480-590 gph range. Mike is letting me borrow his Little Giant to see what kind of head loss I can expect with the chiller. Who knows, maybe the 700 gph Little Giant will be perfect.

Steve