Pump comes after filter?

Discussion in 'General Chat' started by alex chappelear, Feb 12, 2017.

  1. alex chappelear

    alex chappelear

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    hello this is my first post.

    I have heard that the pump must come after all filters and sediment tank so that debris is not broken up by the pump into unfilterable sized pieces? This apparently makes your filter last longer? How much of this is true?

    Also doing the above would mean there is no way to do a seive filter, Just a filter net so that you can maintain suction as pump pulls water to sediment tank then to filter then to waterfall.

    Thank you
     
    alex chappelear, Feb 12, 2017
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  2. alex chappelear

    Meyer Jordan Tadpole

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    Unless your biofiltration is gravity fed the pump must be sited before the biofiltration. Pumps are not manufactured to suck or pull water but to push it.
     
    Meyer Jordan, Feb 12, 2017
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  3. alex chappelear

    Usman

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    hello , its ideal but its not feasible always , it all depends on the design , need and conditions , the benefit is as you have mentioned but the cons are its pressure will decrease as the filter clogs and pump can get dry , need good accurate design and larger setup will need very wide piping and usually bottom drain is needed . i may be getting wrong picture , you can show your pond and your plan or pics to answer better . on the other hand if you place pump inside pond or inside skimmer then the system is fairly simple you just need a bog type filter and ready to go .
     
    Usman, Feb 12, 2017
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  4. alex chappelear

    Mucky_Waters

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    "Must" is kind of a strong word to use in this hobby. It's true that if you want to incorporate a sediment tank or a sieve filter in your pond system then it's going to work a lot more efficiently if it's gravity fed. However, it's no crime to have the pump located directly after the sediment tanks to catch the worst of the bulky stuff and then pump the water to various other filters, and most sieve filters by design have the pumps located directly after them and the water gets pumped onto finer mechanical filters and\or bio-filters.
     
    Mucky_Waters, Feb 12, 2017
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  5. alex chappelear

    alex chappelear

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    Plan is to have bottom drain and skimmer going to a collection box/sediment box then onto a filter. I really like idea of seive but that would cause a break in the chain of suction.

    Could pump be a sumbersible pump within the sediment box to help muffle any sound(I assume external pumps are loud no matter how high dollar they are(this will be 15,000 pond so likely a large pump.

    Original plan was pressurized bead filter from Sacramento koi following their diagrams as they are compact enough to fit under a porch out of view up on a hill, as I have limited space at the level of my pond to have bulky DIY filters. However I have heard Pressurized bead filters don't get the water real clean and are ridiculously expensive.
     
    alex chappelear, Feb 12, 2017
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  6. alex chappelear

    Waterbug

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    Actually a sieve filter must be before the pump to be effective. They are designed to be that way. In high end ponds the sieve's main job is to remove fish poo which is the most concerning solid waste. Things like leaves don't break down as fast or are nutrient rich. Poo breaks up very easy. The sieve also gets the poo out of the water so it doesn't break down and return stuff to the pond water less useful filters do.

    In serious filter systems there are multiply kinds of find each doing a specific job. Generally we're trying to remove larger stuff first. That makes the next filter's job easier, less prone to clogging. So there there sure isn't any rule that a pump should be before or after filters...the rule depends on the filter. A pressurized filter, like a bead filter, sand/gravel, etc..., have to be after the pump. Most types of filters, UV, Shower, Trickle, etc... can go after the pump and it's easier to do so, but most assume some previous filter as removed large stuff first.
     
    Waterbug, Feb 12, 2017
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  7. alex chappelear

    alex chappelear

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    Thanks a lot,

    so a seive filter is gravity fed if pump is after it. It can be placed to receive debris from bottom drain and skimmer? I thought bottom drain must have continuous link to pump to be able to pull water off the bottom and a seive would mean you would break that link/suction?

    I like the idea of a seive but have never once seen one incorporated into pond pluming diagrams
     
    alex chappelear, Feb 12, 2017
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  8. alex chappelear

    Waterbug

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    Submersible pump can go in the sediment box, and most water gardens do this although owners don't always consider a pond to be a sediment box. If you think about it there is no difference between a sediment box and a pond except size. And the bigger a "box" the lower the water movement and more stuff settles out. For some reason many DIY ponders think if they add a box and call it a "sediment camber" that somehow that's where stuff will settle, but virtually all will settle in the pond. Which is where bottom drains come into play, remove the collected sediment.

    I think external pumps are loud, but some people say they aren't. Don't know if it's a hearing problem, background noise or whatever. For a swimming pool no problem, but for a water garden I like peaceful. A large pump is not required for a large pond. Pumps should be sized to water feature aesthetic need, fish load, and devices like some filters, TPRs, etc... There will be a long line of people to tell you pumps are sized to number of gallons in the pond, or surface area, or whatever else they heard last week. That's all has nothing to do with how ponds work and everything to do with the way people work.

    You can add my name to the list of people who think bead filters are poor filters. Personally I've not seen any combo filter work very well. When bead filters first came out most people thought they were the cat's meow, me too. They claimed to be a mechanical filter and a bio filter. Over time they've proven to do neither well...or at least there are better options now. Today sieve is top of the line for mechanical imo followed by lots of things, including bead. Almost all bead filters today are only used as mechanical, first in line, filters. But expensive to run for both electric and water used to flush. Sieve costs zero for electric and no water needed for flushing. Bead still have the advantage of being able to be put on timers, pressure sensors, and therefore be automatic cleaners. But normally a sieve can hold weeks worth of debris so you can be away for awhile and not have a problem.

    For bio top of the line are Shower and Trickle filters. Proven to be about 10x more efficient for the same size as any submerged media filter. And these filters virtually never have to be cleaned. In addition to less work it means they operate at basically the same efficiency 24/7 while submerged drop efficiency between cleanings and as bacteria recover from being covered in muck. Reliable efficiency is very important for pond that need bio filters. Most water gardens don't need any bio filters at all, the pond itself can handle the load, so efficiency isn't really a factor.
     
    Waterbug, Feb 12, 2017
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  9. alex chappelear

    Meyer Jordan Tadpole

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    As I posted earlier, Siting the pump after the settling chamber puts you at the mercy of gravity flow. For a pond with the capacity of 15,000 gallons even using 3" piping will not produce a high enough flow rate to turn the pond volume once per hour. A minimum turn-over rate of 1.5/hour is recommended.
    Plumbing the settling chamber to a separate spur line with a valve for flow control is one work-around option
     
    Meyer Jordan, Feb 12, 2017
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  10. alex chappelear

    Meyer Jordan Tadpole

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    A pump does not per se pull water. In a bottom drain configuration the water is fed to the pump through the principle of water seeking its own level. This is why in most installations of this type the pump is situated in a pit below the water level of the pond. In cases where the pump is above the water level of the pond, the principle of siphoning applies.

    "Pumps DO NOT SUCK liquid into the pump. Rather, atmospheric pressure pushes water into the pump keeping the liquid in its natural state. Even self-priming pumps don't suck liquid into the pump. Because of their design and ability to handle air, atmospheric pressure pushes liquid into the pump by lowering the pressure on the suction side of the pump"
    Crane Engineering
    .https://blog.craneengineering.net/pumps-dont-suck-and-other-centrifugal-pump-basics
     
    Meyer Jordan, Feb 12, 2017
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  11. alex chappelear

    Waterbug

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    Yes, gravity fed. It's a little tricky, but basically it works like a skimmer. There's a constrained inflow, like a 3-4" bottom drain pipe. When the pump is turned on it sucks water out of the sieve which draws down the water level in the sieve creating basically a waterfall. Water flows from the bottom drain to thru the pipe and into the sieve. Most manufactured sieves have a floating door that sides up and down to make sure the pump doesn't starve, but pump size must be within the sieve manufacturer's spec. For DIY sieves the sliding door isn't always needed. The sieve concept has been around for more than a hundred years, probably thousands.

    In theory a skimmer and bottom drain can share a single sieve, and a single pump. But it's tricky. I wouldn't personally attempt it. Maybe I just don't know how, but seems limiting to me. For 15,000 gals I'd assume multiple drains and multiple skimmers. To put all those on one sieve and one pump really seems impossible,

    I think it's easiest to for one pump on the skimmer to feed TPRs and the bottom drain pump feeds filters and water features. Multiple bottom drains are pretty easy to balance with one pump. Same with skimmers.
     
    Waterbug, Feb 12, 2017
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  12. alex chappelear

    Waterbug

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    You are right of course, but we could nitpick about the meaning of the words "pull" and "suck"...not very exact terms. Certainly lots of pumps are installed above the water level and there are benefits like in some cases eliminating flooding in rain storms and shorting out the pump. So I would say those pumps are "pulling" or "sucking" in water. The same is true when a pump is below water level. Position of pump relative to water level affects how a pump is primed. But once primed and the pump is running I'd call it a sucking or pulling action. Same as when we suck on a straw. Water can't really be pulled of course, but close enough.

    Crane Engineering's definition really chaps my hide by saying atmospheric pressure pushes water...I hate junk science. Gravity causes water to seek its own level, not atmospheric pressure. If the earth lost its atmosphere water would still stay in place, pumps would still work, we wouldn't float off into space. Crane Engineering's web site was probably written by a marketing intern.
     
    Waterbug, Feb 12, 2017
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  13. alex chappelear

    Meyer Jordan Tadpole

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    A siphon works by reducing the pressure at one end of a pipe resulting in the fluid being forced by atmospheric pressure towards the end of the pipe with lesser pressure. Gravity plays play little if any part of this physical phenomena.
    The engineering site is correct in this case.
     
    Meyer Jordan, Feb 12, 2017
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  14. alex chappelear

    Mucky_Waters

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    Do a search on youtube to see how pond sieves work. If you have limited space for pumps and filter equipment sieves have a nice small foot print for the job they do, but they generally incorporate an external pump. You can shield quite a bit of pump noise by enclosing them in a insulated box, just make sure you allow enough air ventilation for cooling.
    Not sure where you are located, but you'll want to think about what you'll be doing in the winter to protect you pond plumbing if you live in a cold climate.
     
    Mucky_Waters, Feb 12, 2017
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  15. alex chappelear

    Meyer Jordan Tadpole

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    Cetus_Nexus_GravityFed_Setup.jpg
    NOTE: Sieve has its own dedicated pump.

    Or-
    Sieve_SC.JPG
     
    Meyer Jordan, Feb 13, 2017
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  16. alex chappelear

    Waterbug

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    Now siphons...for anyone who cares: Licence 2011. Also see Gurung 2014. Siphons work in a vacuum and there are lots of pumps used on space vehicles and in space suits.
     
    Waterbug, Feb 13, 2017
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  17. alex chappelear

    Meyer Jordan Tadpole

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    Right....and they are all inside either the space craft or suit where there is no vacuum.
    And all of this has absolutely nothing directly to do with plumbing Alex's pond!
     
    Meyer Jordan, Feb 13, 2017
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  18. alex chappelear

    sissy sissy

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    to e simple is the easiest and cheapest lava rock and a stock tank and tank adapters and you are done .More you do sometimes the more it costs and then if it is not doing the job is it worth all the work and expense
     
    sissy, Feb 13, 2017
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  19. alex chappelear

    Usman

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    neither is responsible solely since siphon has been performed in vacuum successfully without air pressure and also have been done using co2 , more like started by air pressure in tube then gravity plays role

    Gravity, pressure and molecular cohesion were the focus of work in 2010 by Hughes at theQueensland University of Technology. He used siphons at air pressure and his conclusion was that: "The flow of water out of the bottom of a siphon depends on the difference in height between the inflow and outflow, and therefore cannot be dependent on atmospheric pressure…"[28] Hughes did further work on siphons at air pressure in 2011 and concluded that: "The experiments described above demonstrate that ordinary siphons at atmospheric pressure operate through gravity and not atmospheric pressure".[29]

    The father and son researchers, Ramette and Ramette, successfully siphoned carbon dioxideunder air pressure in 2011 and concluded that molecular cohesion is not required for the operation of a siphon but that: "The basic explanation of siphon action is that, once the tube is filled, the flow is initiated by the greater pull of gravity on the fluid on the longer side compared with that on the short side. This creates a pressure drop throughout the siphon tube, in the same sense that 'sucking' on a straw reduces the pressure along its length all the way to the intake point. The ambient atmospheric pressure at the intake point responds to the reduced pressure by forcing the fluid upwards, sustaining the flow, just as in a steadily sucked straw in a milkshake."[1]

    Again in 2011, Richert and Binder (at the University of Hawaii) examined the siphon and concluded that molecular cohesion is not required for the operation of a siphon but relies upon gravity and a pressure differential, writing: "As the fluid initially primed on the long leg of the siphon rushes down due to gravity, it leaves behind a partial vacuum that allows pressure on the entrance point of the higher container to push fluid up the leg on that side".[2]

    The research team of Boatwright, Puttick, and Licence, all at the University of Nottingham, succeeded in running a siphon in high vacuum, also in 2011. They wrote that: "It is widely believed that the siphon is principally driven by the force of atmospheric pressure. An experiment is described that shows that a siphon can function even under high-vacuum conditions. Molecular cohesion and gravity are shown to be contributing factors in the operation of a siphon; the presence of a positive atmospheric pressure is not required".[30]

    Writing in Physics Today in 2011, J. Dooley from Millersville University stated that both a pressure differential within the siphon tube and the tensile strength of the liquid are required for a siphon to operate.[31]

    A researcher at Humboldt State University, A. McGuire, examined flow in siphons in 2012. Using the advanced general-purpose multiphysics simulation software package LS-DYNA he examined pressure initialisation, flow, and pressure propagation within a siphon. He concluded that: "Pressure, gravity and molecular cohesion can all be driving forces in the operation of siphons".[3]

    In 2014, Hughes and Gurung (at the Queensland University of Technology), ran a water siphon under varying air pressures ranging from sea level to 11.9 km (39000 ft) altitude. They noted that: "Flow remained more or less constant during ascension indicating that siphon flow is independent of ambient barometric pressure". They used Bernoulli's equation and the Poiseuille equation to examine pressure differentials and fluid flow within a siphon. Their conclusion was that: "It follows from the above analysis that there must be a direct cohesive connection between water molecules flowing in and out of a siphon. This is true at all atmospheric pressures in which the pressure in the apex of the siphon is above the vapour pressure of water, an exception being ionic liquids".[32]
     
    Last edited: Feb 13, 2017
    Usman, Feb 13, 2017
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  20. alex chappelear

    Meyer Jordan Tadpole

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    Let's get back on topic.
     
    Meyer Jordan, Feb 13, 2017
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