plumbing question

[Waterbug]

1/2" can flow 7 GPM. It has to rain really hard to use up that capacity on the average backyard pond!

I'm not sure where the 7 GPM number is from, but by my calculation it should be 0.5 GPM for a 1" drop, 10' of pipe, no fittings. If the pond is say 30" above ground and/or not on a hill the max gravity flow for 1/2" dropping 30", 10' of pipe, no fittings would be 3 GPM. To get 7 GPM would require a pump or a 12' drop.

A 16'x16' pond with 2.2" of rain (Phoenix building code) in an hour would be 351 gals or 5.9 GPM. So for us 1.5" overflow would be the minmum for that pond.

If you have an external pump in a filter pit, the electric goes out in a thunderstorm so the sump pump doesn't work, and you have a 1/2" overflow...electric comes back on...I'm thinking you just bought yourself a new pump and whatever other electric goodies are in the pit.

 

[EVMIII]

I think that I am going to be forced logistically to violate the basic rule of thumb and try to minimize the impact to the greatest degree possible. This is made a little,more feasible because I will most certainly under stock.

Help me understand the basics:

My BD, as currently designed, will not flow down hill. It will have have about a 1' incline over about 15'. The top of the 100 gallon holding tank will be about 3" higher than the water level in the pool. Will this work? Will the water level between the two tanks?

If i then go from the holding tank to two seperate drums(with a course filter) and the then two more barrels(finer media), then rejoin the two 1.5" pipes into a single pump thensplit again into 1.5" pipes heading to two returns. How big a pump do I need? How o I calculate the flow though the media? I'm definitely beyond my knowledge base.

Help.

 

[Waterbug]

I think that I am going to be forced logistically to violate the basic rule of thumb and try to minimize the impact to the greatest degree possible. This is made a little,more feasible because I will most certainly under stock.

The issues being discussed here don't have much to do with fish stocking level. These are plumbing issues.

Putting in a small tank thinking it's going to be a settling tank isn't going to hurt anything other than your pocket book and build time.

My BD, as currently designed, will not flow down hill. It will have have about a 1' incline over about 15'. The top of the 100 gallon holding tank will be about 3" higher than the water level in the pool. Will this work? Will the water level between the two tanks?

I'm going to ignore friction here to make it a little simpler...

In the world of gravity flow it is the water level between two connected bodies of water that determines flow. When the calculations are done that's what determines flow...not whether the pipe goes up, down, side ways, or even where it connects to either tank.

In this diagram the pipe is much different but the flow inside the pipe are the same. The green line just shows the two tanks are the same level.

In both cases the pump is off. Obviously the water pressure at either end of the pipe are the same.

When the pump is turned the water level in the tank on the right will go down by the same amount in each picture. The amount of water flowing thru the pipe will be exactly the same in both pictures. You can move the pipes in any configuration you like, nothing changes (from a gravity flow perspective).

There are lots of other stuff, but first the above should be understood.

If i then go from the holding tank to two seperate drums(with a course filter) and the then two more barrels(finer media), then rejoin the two 1.5" pipes into a single pump thensplit again into 1.5" pipes heading to two returns. How big a pump do I need? How o I calculate the flow though the media? I'm definitely beyond my knowledge base.

I can't say...too complex for a text description.

I can tell you that flow thru media is done exclusively by rule of thumb and given in ranges by people experienced with the media and similar setups. When inventing your own filter you get to discover that info for yourself.

I can also tell you when I read 1.5" pipe red flags go up. It sounds like you're splitting a 3" into two 1.5" which makes me think you think two 1.5" is the same as one 3"? Two 1.5" pipes carry less than one 2" and of course way less than a single 3" (almost a third less), forgetting the fittings for the moment.

It is complex, but I think you're adding more complexity than needed, which is very normal unfortunately. I don't think you're doing any calculations at all which will get you into a pickle as sure as water runs down hill. Not drawing a plumbing diagram means you will not get any decent advice because people are going to assume they know what you're talking about and tell you about the system they have in their head, not the one in your head. And look luck remembering all this when you're in the dirt with pipes going every which way. Diagram drawing is the first tool to use, not the shovel.

 

[Craig58]

The first column of the chart I provided assumed gravity fed, suction side of a pump system. I take that to mean that if you connected a pipe between two drums full of water, and took a whole bunch of water out of the second one at one time, that the amounts shown are the maximum flows the given size of pipe can flow to refill the second drum from the first. The additional columns were for pressurized systems.

When going from one level body of water to another level body of water, gravity isn't going to play a large role. I'm not sure why you need a gravity calculator for this. If you are talking about a 30,000 gallon body of water maybe. But in a 3000 gallon pond it isn't going to be significant. In one sentence you tell him to use a gravity calculator and in the next paragraph and diagram you show that with level ponds it makes no difference where the connections are placed.

As per my understanding of his design, he's not using any drops in water level, this is purely a level system with all tanks and the suction side of the pump all being gravity fed.

You're making this way more complicated for him then it needs to be IMHO.

I agree about the stock tank. But it isn't going to hurt anything and may help it.

As far as the overflow pipe, I'm not sure what you mean about burning out a sump pump. Where did that come from? We are talking a small pond with a reasonable overflow pipe, probably 2-3 ft to handle the majority of rain falls. Not the Phoenix building code. Why are we comparing a small natural pond to a buildings storm control system? Besides, a sump pit doesn't usually have an overlfow to anywhere else.. It is usually already the lowest point, its why you have a sump pump.

I've had a 1/2 pipe on my 16 x 16 pond for 17yrs (It's only 14" long because it drains out onto my driveway), and I've never had an overflow issue yet. And I know we get more rain here than Phoenix.

Even if the pond were to overflow once in a blue moon, I'm not sure you need to design it to the worse case scenario. I'd rather not see a big old pipe sticking through the wall. a 1/2" is much less obtrusive then a 1.5" The smaller the better. But that is just IMHO. I'll agree that if he got 3-4" of rain in a hour or so, he might overtop the pond. Rains of that nature are few and far between and usually of very short duration. But than maybe a hurricane would do it and in Mississippi that is possible. So in that case it should probably be 2".

Craig

 

[Waterbug]

The first column of the chart I provided assumed gravity fed, suction side of a pump system. I take that to mean that if you connected a pipe between two drums full of water, and took a whole bunch of water out of the second one at one time, that the amounts shown are the maximum flows the given size of pipe can flow to refill the second drum from the first. The additional columns were for pressurized systems.

First column is labeled "Assume Gravity to Low Pressure. About 6f/s flow velocity, also suction side of pump". That means a long pipe with a pump on the end pulling water thru the pipe. The next two columns are a pump pushing water thru a pipe.

When going from one level body of water to another level body of water, gravity isn't going to play a large role. I'm not sure why you need a gravity calculator for this. If you are talking about a 30,000 gallon body of water maybe. But in a 3000 gallon pond it isn't going to be significant. In one sentence you tell him to use a gravity calculator and in the next paragraph and diagram you show that with level ponds it makes no difference where the connections are placed.

I have no idea why the term gravity was used verses say atmospheric. But gravity is why water seeks its own level and it why the water in 2 connected tanks have the same level and also why there is atmospheric pressure. So I don't have a problem with science using gravity to describe this stuff. I got bigger fish to fry.

In one sentence you tell him to use a gravity calculator and in the next paragraph and diagram you show that with level ponds it makes no difference where the connections are placed.

The difference comes from draw down...as I said the diagram was meant to teach one principle...going back to basics.

As to draw down...If the pipe is placed at the very top, say 1/2" down from the pond's water level...when the pump is turned on the level in the tank will (could) drop below the pipe opening. That won't increase flow in the pipe, flow will be determined by the pipe's elevation. If the pipe is lowered flow would be increased. Lower the pipe in a settling can be issue as it can affect settling.

You're making this way more complicated for him then it needs to be IMHO.

I asked the poster if he wanted me to bug him about this. He PM me and asked me to, so I did. I think the poster is probably an adult and can make decisions for himself on what he wants to do. I'm not requiring him to do what I write or even read what I post.

If we are now changing this thread from a discussion on plumbing to evaluating other member's posts then OK. I think you're providing the poster with really bad info which would result in the poster's system not functioning at all IMHO. However, I don't really see how members bitching about other member's posts really helps any thing. But I understand this is an internet forum and this kind of pettiness is part of the process. I'd prefer if we stay on topic and let readers research for themselves to decide what they want to do.

As far as the overflow pipe, I'm not sure what you mean about burning out a sump pump. Where did that come from? We are talking a small pond with a reasonable overflow pipe, probably 2-3 ft to handle the majority of rain falls. Not the Phoenix building code. Why are we comparing a small natural pond to a buildings storm control system? Besides, a sump pit doesn't usually have an overlfow to anywhere else.. It is usually already the lowest point, its why you have a sump pump.

In general, gravity flow systems are placed in what is called a filter pit, because every thing has to be below ground. Normally a sump pump is placed in the pit to keep it from flooding. I have no idea whether the poster has thought that far ahead, is going to use a submersible pump or what ever.

But if anyone wants more reasons not to use an undersized overflow pipe how about seeing your tanks popped out of the ground?

I've had a 1/2 pipe on my 16 x 16 pond for 17yrs (It's only 14" long because it drains out onto my driveway), and I've never had an overflow issue yet.

Super. And if you get that once every hundred years rain storm tomorrow? You might not care but maybe the poster does.

Without using complex calculators there is a more gut way to figure this out. Say you're building a 16x16 pond. If you have a reasonable sized house with a pitched roof chances are each section is about 16x16, we're spitballing here. Well take a look at the amount of water coming off of that roof in any good rain storm. Do you think a 1/2 pipe is going to handle that?

Building code through the US, and I assume most of the world, build to certain standards. Expected snow load, expected wind, expected rain, even expected sunshine. They have to pick a number. Here in Phoenix the number they picked was the highest rain amount expected in the next 100 years which I think is a national standard. Her that was 2.2" per hour. Of course we might never get that in a 100 years, or we might get it tomorrow and again next week. Part of the reasoning is that's it's cheaper to be safe, it's good insurance. Using and installing a 2" pipe vs a 1/2" saves a couple of dollars. The risk of failure on a pond can be hundreds of dollars, not a huge deal, but most reasonable people consider it a reasonable choice. But hey, I get you. I run into people all the time who think building codes are for dummies and they know they can build whatever they think is right and they know better and it hasn't falling down yet, etc. That's their business and the poor person who buys the property or pays for the crappy work.

And I know we get more rain here than Phoenix.

Phoenix yearly rainfall is low, but when it does rain it's the same deal as rain everywhere.

Even if the pond were to overflow once in a blue moon, I'm not sure you need to design it to the worse case scenario. I'd rather not see a big old pipe sticking through the wall. a 1/2" is much less obtrusive then a 1.5" The smaller the better. But that is just IMHO. I'll agree that if he got 3-4" of rain in a hour or so, he might overtop the pond. Rains of that nature are few and far between and usually of very short duration. But than maybe a hurricane would do it and in Mississippi that is possible. So in that case it should probably be 2".

That is your right and I'd always fight for you to have that right as long as the cost of failure is all yours, which it would be in this case. So more power to you bother. I actually like reading about wrecks. When they're brought on by overconfidence they're entertaining and I learn a lot.

 

[EVMIII]

Guys don't worry about hurting my feelings, I fully and completely understand that what I do is solely my decision and the results are mine to deal with. That said

Option 1: BD ->3" pipe -> 100 gallon stock tank -> 55 gl drum -> 55 gl drum -> 55 gl drum - pump (4K p/hr) ->2" out to a wye ->two 2" returns

Option 2: BD ->3" pipe -> 100 gallon stock tank ->split to two 55 gl drum -> two 55 gl drum -> wye to a single 2" into pump -> 2" out to wye -> 2 2" returns

Either option I will tap off of one of the returns to feed my bog.

I also have a Savio filter Skimmer with 55 watt UV that will feed my 150 gallon skippy style biofilter.

I will have a 2" overflow.

The way my pit area is set up it will naturally drain down hill, no sump needed.

I'll have a planted bog, plants in my skippy filter, and plants in my pond.

If you have some thoughts on how to improve this process within these resources I would love to hear them. Thanks to all for the help thus far.

Bud

 

[Waterbug]

Option 1 won't work. 4000 GPH is too much for 3" by more than twice. 4000 GPH connected to a 55 gal drum = dry drum.

Option 2 won't work. 4000 GPH is too much for 3" by more than twice. 4000 GPH connected to two 55 gal drums = two dry drums (probably but too close to call with given info).

Both options, the friction loss in the 2" outflow is higher than I would accept. The friction loss in the two 2" after the wye would still be higher than I would accept. OK, this gets interesting...the friction loss because of the 2" could drop the flow enough to make option 2 work maybe, I didn't check. Also when you say 4000 GPH I assume you mean the actual flow. Heads have not been given, friction not computed and because you're at best right up against the limits I think every calculation is needed.

A bog generally causes a pretty big draw down in the water before the pump. So I think sending water from this circuit is only going to add to the problems.

Most importantly is what will be in the drums restricting flow.

My not working comments are just based on pipe size and flow given. Not near enough info to know anything further.

Suggest changes to consider...
Reduce flow to something more like 2000 GPH. No reason for 4000 that I can see.

Or add another 3" drain. Kind of lame though.

Or add more drums and/or move bio (assuming some of these drums are bio) to after the pump. Pushing water allows higher flow and the drums can be raised to increase gravity outflow. A kind of normal design is: BD -> course filter -> pump -> bio, fine, bog, falls -> pond

 

[Waterbug]

I want to try and explain why your options will or won't work. I gave the simple answer, no. But it's not as simple as yes or no.

For this post I'm only trying to show you a single concept or two...not your pond specifically...just so maybe some of this will make some sense. None of this is intuitive.

Here's a pond and a tank with a pump attached. The red line shows the water level in the tank with the pump off. Obviously when the pump is turned on it sucks water out of the tank.

if the pump pulls water out faster than water comes in through the pipe the level in the tank goes lower and lower (called draw down) until in this case the tank runs dry. That pretty easy. The difficult question is how much water will come thru that pipe? That depends on the pipe size and drop. In this example lets stick with 3" pipe and in this diagram lets say drop is 1", the distance from the pond water level to the top of the pipe (we measure to the top of the pipe only because the water level in the tank went below the pipe).

Bit of a side note....
Note that the tank is open at the top. What happens if we clamp an air tight lid on top? As the pump pulls water out of the tank no air can be pulled in at the top, the only opening is the pipe. As the pump pulls and the pipe flow can't keep up suction builds inside which pulls water thru the pipe faster. This what the chart Craig linked to is referring to. It can move water a lot faster.

OK, back to draw down...
So how much water does come thru the pipe? We go to the calculator and enter 3" pip diameter, say 10' pipe length, and 1" drop and switch discharge rate to GPM and we get 53.4122 GPM * 60 = 3204 GPH. That tells us any pump pulling more than 3204 GPH is going to run the tank dry over some period of time. This is the best possible case...we'd still need to subtract some for friction, fittings, etc.

But it depends on another important factor...
What if we drop the height of the outflow?

Let's say we dropped the pipe 6"? Changing the 1" drop in the calculator to 6" we now see that the max flow is 8433 GPH. That's better.

Because the pump is pulling say 4000 GPH we can compute the actual drop in the tank. 4000 GPH / 60 = 66.7 GPM. Try different drops to get 66.7 GPM (other calculators probably do this for you). About 1.5" drop.

The difference between your filter working or not working is very little difference. It's a small detail.

Obviously you want some wiggle room, so you could plumb the outflow pipe a bit lower depending on how sure you were with getting it right and how stable your pond water level will be. So maybe 3" or 4" down from the pond water level? Maybe 6" or 8" if you're not going to have an auto fill? That's your call. If the top of that 100 gal stock tank is installed 3" above water level and the pipe is 6" down from water level that's 9". 100 gal Rubbermaid stock tank is 25" tall, say 24" inside depth, the bottom of the 3" pipe would be half way down the tank wall. See the problem with why it wouldn't be much of a settling tank?

Domino draw down...
Say after the tank above you connected another tank.

This calculation is more complex so I'll just say the level in the added tank will be even lower. As to add tanks in series the levels drop in each tank. That effects what height each pipe can be plumbed and whether the tank the pump is connected to will run dry.

Hoped that helped a little about how little tiny details can add up to a failed or successful build. And also I hope you see that even though I said both your options would fail, that is not completely true. It depends on where pipes are exactly and a lot of other little details. But the options given didn't look good imo.

Without knowing any of this you could just get lucky and your system runs like a champ. Just happen to get each pipe at the right level, etc. But because there's lots of details the odds are against you.

 

[Craig58]

I do agree with most of what Waterbug is saying above.

I'm assuming the inputs to each drum are near the bottom, with the output near the top.

You have the resources you have.

So run a few tests.

Take one drum. You know you'll have either an input or output near the bottom of the tank.

Install a 1.5" pipe near the bottom. Fill the drum, measure the time it takes for the drum to empty. (make sure you fill first to where the water drains out. Close off the pipe. Fill with 5 gal buckets of water. Now you now exactly how much you are draining off.)
If you want to,fill the drum with the filter material you intend to use.
If the flow isn't what you want, replace with a 2" pipe and test. If not good enough, replace with a 3" pipe. No need to go more than 3" as that is all your drain line is.

Nothing replaces doing an actual test run.

Once you determine the necessary pipe size, you'll know what size to connect your drums with and what minimum flow rates are possible. You might achieve higher rates once the pump is attached but as the media clogs it will get reduced too. But at least you'll know what is possible before building out the whole system.

I agreed the stock tank won't make a great settling tank. But if it's a resource you have and you want to use it, I don't see the harm in doing so. You might consider putting in some larger mesh material to help capture some of the bigger stuff and use it more as a pre-filter.

I also think you'll still need a bypass line that goes around the filters and ties back in on other side. You might need to reduce the flow rate going through the filters to get good results and that you'll only know that by actually running it. Best case is you don't need to use it at all and the filters handle all the flow. Then you'll have a way to bypass filtration when medicating the pond or when cleaning out the filters.

Craig

 

[EVMIII]

Waterbug and Craig,

Thanks much guys for you help, it is starting to make some sense to me (believe it or not I am a rlatively eduacated fellow). A couple thoughts:

1. When i have been referenceing flow rates it has been sololy based on the max capacity of the pump. I am slowly learning how many variables will reduce the actual number.

2. What I am calling a settling tank is most likely alot more like a pre-filter. My plan is for that to be setup to encourage crap to settle and run through a couple course filters. Supllimental filters will get finer as they go.

3. I understand the trial an error part of this process that i will endure. I have a plan to temporarily plumb some of this to test flows through differnt filter medai. I need to get some mroe specific elevations before i can go much further.

One more question for now

What is the desired pressure range coming out of a return? I am planning my two returns to be about a foot from the bottom directing flow towards the BD. I am thinking 1 1/2 inch pipes becasue i have some pool style thread on ball directional flow ends taht I can use to fine tune the flow.

Thanks again for the information.

Bud

 

[Waterbug]

2. What I am calling a settling tank is most likely alot more like a pre-filter. My plan is for that to be setup to encourage crap to settle and run through a couple course filters. Supllimental filters will get finer as they go.

I'll not bug you you further beyond to say it's the same basic issue. By pre-filter I assume you're talking about mats, pads or something like that because settling tanks are also pre-filters.

One more question for now

What is the desired pressure range coming out of a return?

You want the most you can get. That may sound patronizing but it's the basic truth. Kind of everything else you do, or should do, is geared toward that goal. A garden hose will spin water in even a very large pond. It's just the faster the water currents the better the cleaning function. And if you're paying $$$ to move water you may as well get everything out of it you can.

I am planning my two returns to be about a foot from the bottom directing flow towards the BD.

Hopefully you mean they'll be pointed off to the side not actually towards the BD, unless this pond will be a river flow design, not circular (I forget if you've said). If not it's another topic you should check out.

I am thinking 1 1/2 inch pipes becasue i have some pool style thread on ball directional flow ends taht I can use to fine tune the flow.

The size of the pipe should be the last decision to make. What's coming into a pipe should drive diameter choice. But there are of course things you can do to make 1.5" work just fine, that's in the details.

 

[Craig58]

Agree with WB above.

When picking the size of the return pipes you want to balance the friction loss with velocity. Reducing the size of the line increases the friction loss thus requiring more pressue to push the water through the pipe to get the same flows. Friction loss becomes more critical the smaller the pipe. It's why we in the fire service have moved to large diameter hose. Technology has allowed us to move from the older 3" supply lines to 4, 5 and even 6" supply lines on the trucks. Once in the 5" range, the friction loss is so negliable for the length of hose we can carry on an engine that we can almost ignore it with regard to pump and waterflow calculations.

In your pond, the same hold trues. Also, try to reduce any fittings and sharp turns. That increases the pressure loss as well. It's why we usually try to use either flexible pipe with gentle bends and turns, or is PVC is used, try to make the returns as straight at possible with minimum turns.

So once you determine a ball park area of your pumps output after the filters, you can select the right diameter of pipe. Going to large can't hurt but can reduce the velocity of the return flow into the pond which can reduce it's effectiveness in using it to guide debris to the BD. But if you simply send it all to a waterfall, you might want a large pipe return to intentionally reduce the velocity and force of the water entering the waterfall reservoir. If the pump outputs a 2" line, and you use a 1.5" to the waterfall, that steam of water exiting the pipe could be pretty strong. Take the same 2" line and use a 4" line to the waterfall, the strength of the flow will be greatly reduced with no where near as much force behind it.

If you split a portion to your bog, you might want that to have a low velocity entering the bog.

Craig

 

[Waterbug]

What is the desired pressure range coming out of a return? I am planning my two returns to be about a foot from the bottom directing flow towards the BD. I am thinking 1 1/2 inch pipes becasue i have some pool style thread on ball directional flow ends taht I can use to fine tune the flow.

To be more specific to my "You want the most you can get" answer...what Craig says is true for moving the largest volume of water, larger the pipe the better. But specifically for the returns, assuming you're talking about TPRs, it is pressure that you want the most of and a good target would be 1000 GPH even if that requires some loss in volume. For example having four 3" TRPs with a 4000 GPH flow would not be good imo even though friction loss would be very low.

What I do is once I know the GPH being sent to the TPRs I check the friction loss for the standard pipe sizes. For example, say 4000 GPH is split to 4 TPRs, so for 1000 GPH on each TPR, say 10' of length:

Pipe __ Loss
1" ____ 32"
1.25" _ 11"
1.5" __ 5"
2" ____ 1"
3" ____ 1/4"
4" ____ 0"

I look at that and think 1.5" or 2" would be the sweet spot. That gives me the best ft/sec and volume imo.

The above is when a pump is pushing water thru the TPRs. The pump adjusts to the pipe, meaning it would work with even a 1", just less water for the same electric. With gravity flow TPRs you don't have that flexibility. In that case you have to use the gravity flow calculator to make sure the pipe is large enough so filters don't backup and overflow, but not so big that there's no back pressure at all. The height of the reservoir can be adjusted also.

You always end up with a chain of events in these systems. So you always have to look at the entire system as a whole.

 

[crsublette]

Waterbug, quick question if you don't mind about the gravity calculator; I found that calculator sometime ago as well. My question is ... It is my understanding that a braided hoses or flex pipe will have a higher roughness coefficient variable and this noticeably affects the gravity flow. Can you explain the roughness coefficient variable and do you know of any good charts or how I could go about asking to know of it for a particular pipe?? sorry for the run on question.


EVM, for your 90 degree fittings, use what is called "smooth" 90s; the normal 90 degree fitting you typically see is a "hard" 90. A "smooth" 90 is like a elongated curve making a 90 degrees. Also, two 45 degree elbows can make a smooth 90.


Awesome thread. EVM, trust me. Waterbug knows his engineering ... after reading all the advice about walls and other stuff, i think he is a construction engineer in real life.

If you really want to get crazy detailed, Boggen appears to be the flow engineer at Koiphen. Check out:
understanding currents within a pond to obtain idea of self cleaning pond ((this will show you where and how to place the pond returns))
plumbing, head, gravity flow, system curve, etc ((tells ya everything else, giving exact equations, about info Waterbug is saying))

This is good stuff. Waterbug is giving you the "cliff's notes" version of it with pretty pictures , which is very awesome because these two threads I hyperlinked are huge.

As per my understanding of his design, he's not using any drops in water level, this is purely a level system with all tanks and the suction side of the pump all being gravity fed.

In general, gravity flow systems are placed in what is called a filter pit, because every thing has to be below ground. Normally a sump pump is placed in the pit to keep it from flooding. I have no idea whether the poster has thought that far ahead, is going to use a submersible pump or what ever.

Welp, EVM, there is an option if you do not want this gravity flow system to be even with the pond level. You can use airlifts to make up for it. Airlifts can move a ton of water in a vertical pipe that costs much less electricity versus a pump. Only downside is airlifts do not have the PSI that pumps have. Airlifts just meant to move water vertically. Don't think it can be done horizontally, at least I never seen it or read it explained yet. Check out. What would you like to know about the USE of airlifts?? Good thing about airlifts is they don't ruin when the chamber runs dry.

Super. And if you get that once every hundred years rain storm tomorrow? You might not care but maybe the poster does.

Yeah, I agree. Should take into account of such things if you don't want that one crazy flash flood storm to cause you troubles. In my area, we're "supposed to" get 13"~18" of rain (which hasn't happened in 15 years) and a 3" rain within one hour is extremely rare, yet it has happened.

 

[EVMIII]

All you guys are awesome. I am learning a ton through this thread nd the others I've been reading.

I shouldn't have any problem with the gravity flow system getting my tank water level with the pond. I'm heading now to the link above on currents, but I do understand the flow desired (not aimed at the BD like I stated earlier).

Another question for all:

Assuming I am going to use a 100 gallon stock tank and five 55 gallon drums

BD ->3" pipe -> 100 gl prefilter- ->2" pipe -> 55 gl course filter -2" pipe 55gl fine filter -> 55 final -> pump -> 2 tpr's
->2" pipe -> 55gl course filter -> 2" pipe 55gl fine filter->

My thinking that with the 3" pipe from the bd bringing enough water for two 2" and the pump pulling from the combined final drum I could tweak it with the pump to make it work and have maximum pressure going out to the tprs.(I understandthis is very simplistic and there are a bunch of variables)

Is my thinking way off track? Thanks again or all of the help.

Bud