Question for the Pond Experts - Can I reduce Flow?

[Tidybuoy]

My pond pump is too powerful. I tried a smaller pump and it puts out too little. My current pump is creating a waterfall that is almost like Niagra and way too loud.

I'm wondering if it will damage the pump for me to add an in-line ball valve where I can adjust the water pressure.

Any advice would be appreciated.

Vern

[stevej37]

Maybe put a T in the line to the waterfall and direct the second line back into the pond?

[1990C4S]

Yea, diverter T with an orifice in one of the output lines. Maybe make a simple flow control.

[masraum]

I like the above idea of a diverter valve. If it's a valve then you can "tune" it as 1990C4S said.
The only other thing that I could think of which may be problematic would be adjusting the voltage or current to the pump. I know that in some circumstances reduced voltage or current will slow something down without causing issues, but then in other cases, it can harm equipment. I'm not sure how to determine if your pump is the former or latter.

[911 Rod]

Why not just a valve on the line?

[id10t]

Originally Posted by masraum

I like the above idea of a diverter valve. If it's a valve then you can "tune" it as 1990C4S said.
The only other thing that I could think of which may be problematic would be adjusting the voltage or current to the pump. I know that in some circumstances reduced voltage or current will slow something down without causing issues, but then in other cases, it can harm equipment. I'm not sure how to determine if your pump is the former or latter.

Putting a PWM on the power circuit may be able to do that for you, though I think they only work w/ DC stuff... all I know about 'letrissity is that it is to be respected 'cause it can kill you ded

[masraum]

Originally Posted by 911 Rod

Why not just a valve on the line?

Would a valve that limits flow stress the motor with backpressure?

[911 Rod]

Originally Posted by masraum

Would a valve that limits flow stress the motor with backpressure?

Not sure, but we do this everyday with a well or lake pump.

[vash]

I got a "B" in fluid dynamics. from memory, you won't hurt your pump. I remember everything you add downstream of the pump will add friction. elbows, T's, length of pipe. you could T it off and run a secondary outlet underwater somewhere for added current.

I think if you choke it off with a ball valve type thing, the water exiting that valve will increase in velocity (velocity = flow/area - I think). might be even more noise and excitement.

[masraum]

Originally Posted by vash

I got a "B" in fluid dynamics. from memory, you won't hurt your pump. I remember everything you add downstream of the pump will add friction. elbows, T's, length of pipe. you could T it off and run a secondary outlet underwater somewhere for added current.

I think if you choke it off with a ball valve type thing, the water exiting that valve will increase in velocity (velocity = flow/area - I think). might be even more noise and excitement.

Agreed, reducing aperture will increase pressure/speed.

[masraum]

Originally Posted by 911 Rod

Not sure, but we do this everyday with a well or lake pump.

There you have it, a man speaking from experience. This sounds like the way to go. (assuming pressure/speed increase isn't a problem).

[911 Rod]

Originally Posted by masraum

There you have it, a man speaking from experience. This sounds like the way to go. (assuming pressure/speed increase isn't a problem).

I nothing but .....when using the sprinkler with my lake pump I adjust the height by closing my valve a bit.

[Rusty Heap]

simple. speed controller on motor.

[wdfifteen]

Originally Posted by masraum

Would a valve that limits flow stress the motor with backpressure?

The greater the head pressure, the harder the pump has to work.

At the very least, throttling the line will use more electricity because the pump is working harder.

Working harder means more heat, which will shorten the motor's life. Significantly? That would be up to you.

Worst case scenario is the flow is so restricted, there isn't enough water flowing through the pump to keep the motor cool. That will cost ya.

Adding a tee and a line back to the pond with a valve in it that would control the bypass flow would be the best option.

[john70t]

If it's purpose is to put O2 into the water and clean it up, consider an aeration diffuser system instead of sprinkler fountain.
Makes more sense to move air instead of water.

[Tidybuoy]

Originally Posted by 911 Rod

Why not just a valve on the line?

This is what I got and will install this weekend. I'm thinking I only need to restrict by about 25% and this will be the easiest solution. Time will tell if it's hard on the motor but they are not extremely expensive - about $150

[Tidybuoy]

Originally Posted by john70t

If it's purpose is to put O2 into the water and clean it up, consider an aeration diffuser system instead of sprinkler fountain.
Makes more sense to move air instead of water.

I have an air pump and a diffuser. This pump is recirculating the pond water to a filter and then back to the pond via waterfall. If the ball valve doesn't work (i.e., increasing pressure & sound) then I will divert the water to another area of the pond. I already have two 1.5" lines feeding the waterfall and moving one of them to feed directly into the pond is an easy fix. If I go that route, I have simply added a shutoff valve and that is no big.

[masraum]

Originally Posted by wdfifteen

The greater the head pressure, the harder the pump has to work.

At the very least, throttling the line will use more electricity because the pump is working harder.

Working harder means more heat, which will shorten the motor's life. Significantly? That would be up to you.

Worst case scenario is the flow is so restricted, there isn't enough water flowing through the pump to keep the motor cool. That will cost ya.

Adding a tee and a line back to the pond with a valve in it that would control the bypass flow would be the best option.

That's what I was thinking (in much less detail). Seems to me that the best solution is to be able to vary the pump volume/time (why I was thinking about vary the voltage/current) (AKA "speed controller on motor" as Rusty Heap said).

[Rusty Heap]

pick your wattage.......... $30.

https://www.amazon.com/s?k=ac+motor+speed+controller&crid=2ZVMV8FVREFI7&sprefix=ac+motor+speed+controlle%2Caps%2C194&ref=nb_sb_noss_2

[red 928]

Restricting the discharge flow will reduce
the load on the motor.
At deadhead conditions, the HP requirement
it at it's very lowest.

But it can also cause low-flow recirculation
in the impeller.
That causes hydraulic turbulence and vibration
and could reduce the life of the bearings and impeller.
But on a low-energy pond pump
it probably wouldn't be that big of a deal.
As mentioned above, the best way to do it would be
to reduce the speed of the pump.