cacluating pump for pond plus stream

[Waterbug]

Filters to me are things that are used when needed and are expected to perform a certain task. To sellers and many people filters are just this can of random thing that "you must have". Without knowing anything about your goals I have no clue to be able to say what filter you need where. I'll will say I haven't noticed anything in this thread that tell me you need any filter any place. But you've said very little about what you're doing or your goals so I don't know anything.

The outlet on a pump isn't always the best pipe size to run. Many people think that the smallest point in a system limits the rest of the system so no reason to use bigger pipe. All goes back to the friction calculations.

Right out of the pump water is at a higher pressure, which means more loss due to friction. A 1-2" length of 3/4 pipe may not be that much of a loss, but 20' could be a be difference. So the best thing to do imo is at least a rough calculation on GPH and pipe size.

There are fittings to change size. You might not find a fitting that goes from 3/4" to 2", so maybe you go from 3/4" to 1.5" and another fitting to go to 2". That type of deal. And there are various ways these fittings go together. For the best selection and price you can't beat Plumbing Supply. I've been into a Home Depot or Lowes about 7,873 times and not once did I ever find all the parts I needed. Now I just plan ahead and order on line...no matter how small the order.

In addition to size you also have to deal with material. Most "tubing" is not any kind of standard anything. So connection points can be interesting to figure out.

 

[randythawkins]

about 7,873 times

*about* an exact number of times. makes me laugh. Those are the kinds of things I babble out.

 

[garyoddou]

Thanks again for the useful info. In terms of more info about what I'm doing, I just want to build a rock waterfall, have it go into a stream and then to the pond. I do plan to have water plants in the pond and some plants along the stream and beside the pond, interspersed among the rock. I don't know if that helps you to know how much I need a filter or filters and where.
On the outlet from the pump, it sounds like I could put a 3/4 fitting on the outlet side and the other side of the fitting be larger and go as quickly as I can from 3/4 to 1.5, for example, without any hose being involved so once the hose begins, it's the same diameter all the way to the waterfall. Does that sound like a good idea to avoid more friction loss than is necessary. I'll take a look at Plumbing Supply. I can probably answer my own question.
With your help, I think I'm much closer to knowing what to do and being somewhat confident in it. Thanks.

 

[Waterbug]

*about* an exact number of times. makes me laugh. Those are the kinds of things I babble out.

I watch too much Star Trek. Spock is funny.

 

[Waterbug]

Thanks again for the useful info. In terms of more info about what I'm doing, I just want to build a rock waterfall, have it go into a stream and then to the pond. I do plan to have water plants in the pond and some plants along the stream and beside the pond, interspersed among the rock. I don't know if that helps you to know how much I need a filter or filters and where.

When I design a pond for someone I want to know how much maintenance they'd be OK with given a certain budget, how many fish, type of fish, etc. It's a whole deal. They're new to ponds, they don't know what to ask. My job is to get into their heads and figure out what they've imagined the pond will be.

Best to just keep asking and answers will lead to more questions and after awhile it will start to make sense.

You haven't mentioned fish so you sure don't need a bio filter. Besides, that size stream is a great bio filter.

There are filters to remove small stuff suspended in the water. Doesn't sound like that would be a concern.

There are filters to kill green water algae. Green water in a stream will normally appear clear. So that doesn't sound like an issue.

There are filters that keep leaves and stuff from clogging the pump. We call those pre-filters. Mass market submerged pumps come with screens and foam on the intake...that is the pre-filter. You can add a bigger pre-filter either by buy one or making one. This only puts off the problem a little. Pre-filters have to be cleaned, sometimes daily. In the fall maybe every hour. Personally I hate pre-filters and I've designed and built many including one as large as a trashcan...they all clog. I rip out the foam thing and just go with the cage. Then I place the pump someplace where clogging is reduced. Behind the skimmer or in the top 1/3 of the pond (off the bottom).

On the outlet from the pump, it sounds like I could put a 3/4 fitting on the outlet side and the other side of the fitting be larger and go as quickly as I can from 3/4 to 1.5, for example, without any hose being involved so once the hose begins, it's the same diameter all the way to the waterfall. Does that sound like a good idea to avoid more friction loss than is necessary.

You've nailed it.

With your help, I think I'm much closer to knowing what to do and being somewhat confident in it. Thanks.

You're welcome. Always happy to talk about interesting pond designs like yours.

 

[garyoddou]

Thanks for the info on filters/prefilters. We only have one tree--jacoranda (drops a lot of flowers during a one-month period and twigs at other times)--and I don't plan on putting the water landscaping anywhere near it. Other than that, we have a lot of Giant Birds, a few Australian tree ferns, sago palms and other palms (Kings and Queens, etc.). My plan is to put the waterfall, stream and pond where giant birds will not fall into it when they have to be trimmed, etc. Still, I'm sure there will be the usual wind-blown debris that will sometimes make its way into the pond or stream. Would you suggest, then, just putting a "macro" filter cage/strainer of some sort in front of the pump and leave it at that? I can put the submersible pump on a rock or something to lift it off the floor about a foot (the pond is only 18 inches deep).
No fish for sure. We definitely want this to be as low maintenance as possible and we are sometimes gone for 2 months.
Any recommendations on pumps? I was looking at Pondmaster mag-driven pumps because they seem reasonably priced, have a long warranty period and seem solid. I'm open, though, and would rather spend more money on a good pump that won't give me grief than to barely get by. The volume of the pond is less than 500 gallons, the stream about 20 feet, 36 inches wide and the waterfall 3 feet tops (I was thinking of doing a two-step water fall to the stream.) and with a 14-16 inch weir. It's the weir that seems to be upping the gph for the pump quite a bit; otherwise, I was looking at a pump that pumps about 1200+ gph at 0 head but with the waterfall around 3 feet and the weir, it seems like I should be looking more at a 2500 gph pump. Am I way off or what other info would you need to know to help me figure the pump size out?
Thank you.