What size pump for pond/bog/stream?

[Huckleberry12]

I am calculating the size Laguna max-flo pump I need. I was going to have a line going to the bog and another to the stream but realized that would be pumping double the volume, so have returned to having the pump overflowing into the stream (sole feed to stream). Here are the numbers:
Pond, bog, stream 900 gallons
I' head. 100
4" weir. 400
8' hose to bog 80
Total. 1480 gph

I didn't add anything for the pipes in the bog, but I'm over 1350, so presumably should get the next one up which is the 2000? I'd appreciate confirmation on this since two pond people in stores both said 960 and Laguna, when I asked them, said 1350 (they didn't include anything for the weir). Thanks for the help - I'll get this pond done and working yet!

 

[sissy]

Depends on how much water you want flowing .The 2400 gph laguna feeds a filter and a uv and extra goes in the pond to aerate it .

 

[Huckleberry12]

Hi Sissy - What I want is water flowing through the bog and into the stream with a flow 4" x 1/4". It seems that 1350 gph won't do it, but according to my calculations (which may be missing something) the 2000 would. Am wanting to check on that. I'm not planning on a filter other than the bog, nor UV.

 

[tbendl]

Huckleberry, you are planning on having fish right? From what I understand you can't go wrong with extra pump but can go drastically wrong with less. Unless the money is significantly different, I would go with the 2000. Like Sissy did you can always split the flow if the rate is too much for your bog.

 

[Huckleberry12]

Tihanks, tbendl. That's my inclination too. Going smaller is such a risk. And yes, my four goldfish are eagerly awaiting having more space!
April

 

[tbendl]

I lived in BC for awhile. Prince George actually. I loved it there. Can't wait to see pictures Huckleberry.

 

[MitchM]

Huckleberry, here is a head loss calculator that you may find helpful.

http://www.everything-ponds.com/head-pressure-wizard-advanced.html

 

[Huckleberry12]

Really, tbendl! I haven't actually been to Prince George. I moved to the coast from Ontario 25 years ago and mostly stay here by the ocean. Got a little further today before the rain started. Am working on the bog now. Here's a photo from the end of the work day:

You can see the murkiness of the water from the drain rock and pea gravel, even though I had washed it first.
Thank you for that link, Mitch! There seems to be a lot of useful stuff on that site. I'll have to go back and look over it some more. I actually think I over estimated the number of gallons; think it is more like 800 rather than 900. But their pond calculating wizard suggests 800 gph, as opposed to the 1130 that Laguna recommended (meaning the 1350 gph pump since the one down from that is 960). Neither were taking into account the bog, though I did mention it to Laguna. This is what gets me about ponds. There are such very different recommendations depending on where you look. So I'm extra glad I can ask questions here!

 

[Meyer Jordan]

Go with the 2000 gph, you will be glad that you did.

 

[Huckleberry12]

Mitch, the site you reference talks about "head pressure" and how connections in the pipe, for example, increase the head pressure (the combination of forces the pump has to overcome to pump water from one end of the system to the other). This raises something I have been wondering about and that is the head pressure created with a bog - the water flowing into those pipes with slits in the bottom, at the bottom of the bog. This seems to be of some significance when it is the overflow that is feeding a stream. Yes?

 

[MitchM]

Head loss calculators only take into consideration the pipe that the water has to move through and how far you are pumping the water above the originating water level.
They do not take into account any other restrictions that you may put in, such as drilled holes or slits in the outflow pipe.
It is better to get an oversized pump that you can scale back the outflow, rather than try to get too exact with your calculations.
Whatever size pump you come up with after all your calculations, get at least the next size up.

 

[Meyer Jordan]

A simple formula for determining pressure.
P=0.434h*SG

where P is pressure
h is total head
SG is specific gravity of the fluid.
In this case SG is 1. Water has a SG of 1.

 

[addy1]

Yep go bigger

 

[Huckleberry12]

Okay! I called and asked the nursery to put aside a 2000 gph pump for me and I'll pick it up on Thursday. I feel very good about this decision and thank you all for your input.

 

[MitchM]