Pump and Pipe size question.

[nine9d]

Hey everyone, I just purchased a Vivosun 9000 GPH pump and it comes with a 2" barbed insert. From my understanding, wouldn't a pump rated at this pressure need a 3" pipe to be able to handle that much gph efficiently? Thanks so much for any help you can give me. I don't want to mess up with building my new pond.

 

[Mmathis]

I really can’t help, but wanted to say hello and welcome!

 

[j.w]

and welcome @nine9d
No clue on that pump!

 

[Jhn]

In short yes There would be less flow restriction going up to a 3” pipe, but 2” would suffice. Most here use flex pvc in either 2 or 3”, just don’t use the barb fitting and hit up the plumbing dept. of one of the big box stores, to get the parts you need. I know I never use the parts that come with the pumps I buy.

For example I have a10,000gph variable speed pump that runs wide open all the time, pushing water through 2” flex pvc and it pushes mor3 than enough water for me to get the look I want in the waterfall. I don’t really over think things when it comes to ponding it is more of the K.I.S.S. Approach

 

[nine9d]

Wow! Thanks everyone for sure the warm welcome.

And thanks for your responses as well. I come from the world of reef tanks and I know how critical we are with flow rates and all that jazz. I really wanted some assurance as to what I am doing is right, because so far I am having a heck of a time finding 3" fittings made for pumps. I did order 3" flex pvc for the pump, and then I was having second thoguhts if I was spending money needlessly by going with the 3" items.

Thanks again for any further help!

 

[combatwombat]

It kind of depends on how far you’re going with the pipe and how much flow you’re looking for. Most pumps run their best with a little head pressure against them.

If you’re trying to get a close as possible to 9k GPH and you’re running 50’ of pipe, you definitely want 3”. If you’re just running a few feet and don’t mind some loss of flow, 2” is fine.

Here’s a good reference for this kind of stuff:

Plastic Pipes - Friction Head Loss vs. Water Flow

Friction head loss (ft/100 ft) vs. water flow in plastic pipes like PVC, PP, PE or PEH.

www.engineeringtoolbox.com

Agree with @Jhn about fittings.

 

[nine9d]

Ahh, thanks so much for that info. Guess I should have given more info. I will be going about 18' run with an incline about 4'. I wanted to maintain as much pressure as possible to make sure I had a good pond turnover rate. Thanks so much!

 

[Jhn]

How big is your pond? And what are you trying to keep in it?

The difference in flow from 2-3” piping isn’t going to mess up your pond. Unless you are trying to keep a dedicated koi pond. Eco ponds or hybrids are much more forgiving on flow and circulation, as plants are doing most of the filter work be it in a bog or in the pond proper, along with the SSA created by the gravel in the bogs you end up with a huge biological filter.

Flow rates aren’t that critical in ponding like it is in reef tanks. Smaller ponds, yes hitting the 2x an hour turnover of pond volume is a little more critical, the larger the pond not so much.

For example, Currently now that I enlarged my pond, I am just hitting 1x an hour in turnover or circulation about 10,000 gallons per hour going to the waterfall , and 3,000 gph per two bogs ( roughly 16,000 gph circulating but only 6000gph going through the “filter” ie the bogs) but my pond went from 10,000 gallons to 20,000 gallons, and the water circulates from one end to the other. There is also two 2000gph power heads, moving water towards the intake bay and an air pump. The pond actually has better circulation now with less turnover than it did when it was smaller.

 

[brokensword]

here's a tip a pro pond builder once told me; right from the pump outlet, increase the sizse for better flow/efficiency. So get a 2" to 3" adaptor and run your hose. Or, as in my case, I increased from 1-1/2" to 3", then added a 3" wye with one leg reduced to 1-1/2", and reduced the other leg to also be 1-1/2". The two feeds give more flow now than the original 1-1/2" outlet would have. It seemed counter intuitive to me but it works!

 

[nine9d]

The pond will be about 5,000 gallons all said and done. I am planning to have a bog as well. I will be keeping a few Koi and whatever local wildlife find their way to the pond.

 

[nine9d]

here's a tip a pro pond builder once told me; right from the pump outlet, increase the sizse for better flow/efficiency. So get a 2" to 3" adaptor and run your hose. Or, as in my case, I increased from 1-1/2" to 3", then added a 3" wye with one leg reduced to 1-1/2", and reduced the other leg to also be 1-1/2". The two feeds give more flow now than the original 1-1/2" outlet would have. It seemed counter intuitive to me but it works!

That's pretty interesting. Thanks!

 

[gello22]

There isn't a pump curve that I could find but they did publish the max lift and most pumps follow pretty close to the same equation.
With 18ft of smooth hose 4ft rise and no elbows, elbows will make a difference especially hard 90s. I assume the rise is above the level of the pond because the submerged depth of the pump cancels out.

2" hose about 7000gph
3" hose about 8000gph

again that is without elbows I got 7166 and 8160 but without an actual curve I would say you are around 7000gph and there is about 1000gph difference between them or about 14%.

 

[nine9d]

Wow, thanks so much for that info gello22! I guess I could be stressing over something simple as some have told me. But 1,000 gph is a lot of flow if you really are concerned.

 

[MTguy]

Before you do all of your fittings, you may want to take a look at this article. It's old, but I found it quite helpful for my current project. https://www.pondtrademag.com/do-different-pvc-fittings-really-make-a-difference-in-water-flow/

The difference between a 90 degree fitting and a 90degree sweep fitting could result in a 12% difference in flow, and that is just for one fitting!