A O U Building a Pond

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This will be broken down into 3 sections: The Pond, The Filter & The Waterfall. It should be understood at the outset that if one talks to 100 Ponders (Pond aficionados), one will get about 350 ideas on how to best build one, mainly consisting of: "How I built this one (100)", "What I wish I had done (100)" & "My next one is gonna be like (150)".

Essentially what we (my son with my, ahem, direction) did is just dig a hole in the ground in the shape we wanted to use and put a liner in and filled it with water. You may want to outline the area for your pond by using rope (or even garden hose) or stakes first to get an idea.

Liners can be gotten from pet stores that have aquarium sections or one can be made from rubber roofing material (check your yellow pages for roofing contractors - you might get lucky and find one who has a large piece left over from a job).

My first pond used the former (and was in the ground for 8 years, then removed and is now being reused as a pond liner in my son's front yard.) and the replacement is rubber (60 mil thick). Liners can cost from $100 to around $300, depending on size, type, etc. I kinda like the rubber because you can cut and glue it to pretty near any shape you want. With the regular pond liners one is confined to whatever size is bought.

Also many ponds are cement lined and smaller ones often use a pre-formed fiberglass shell. Essentially what it boils down to is a hole in the ground lined with something that will hold water.

If it's put in an area with trees or where rocks work their way to the surface, you oughtta line the bottom of the hole with something to protect the liner so the roots/rocks don't poke a hole in the bottom. Several inches of newspapers and/or old rugs work well. Probably a good idea to do it anyway. It acts like a buffer between the weight of the water pressing down against anything that might work its way up/under the liner.

The pond should be deep enough so the bottom is below the frost line in winter so the fish won't freeze. But if it isn't, you can always put in a small heater to keep a small area open. I've never used a heater and swear that one bitter cold spell it froze clean to the bottom (it was 18" deep then, it's now 30"). You could actually see the fish frozen in the ice. I only lost maybe 10% of the fish so it really didn't bother them all that much. (There's a link to a dandy homemade pond heater diagram on the Pond Links page, address at the end.)

In the bottom of the pond put white gravel (I recommend 3-4"). It does four things:

1. It vastly increases the surface area for bacteria to grow on that break down fish wastes, water discoloring algae, and other organic matter. (See UG filter further on)

2. It provides a base for plant life to root in.

3. It gives the fish something to root in for food (algae)

4. It provides a light background to look into - You'll be able to see the fish and other stuff a lot better.

Finally, a rule of thumb is, "Bigger is better". No matter how big you make your pond, after a while you'll probably wish you had made it bigger. Another advantage is that the more gallons, the larger the buffer for environmental changes. For example, it warms/cools slower, allowing the fish time to better adapt. Generally it's not much more time consuming to take care of a large pond as a small one.

It's important here to remember one rule - The filter(s) can only be too small, not too big. If you don't mind green or cloudy water, and only want a few fish, you can ignore this rule. Generally the more filtration, the more life you can support. If your pond is in direct sunlight (mine is) it will generate a lot of algae and become nearly opaque without a good filtering system.

Essentially filtration boils down to three kinds:

1. Mechanical - which physically removes matter from the water.

2. Biological - which uses bacteria to break down matter (particularly ammonia) into stuff that can be utilized elsewhere.

3. Chemical - which kills algae and bacteria that would otherwise discolor the water.

One other thing, when I'm talking about algae, I will generally mean the water borne kind that discolors the water, the kind that biological filters take care of. There are all kinds of algae and the kind that grows on surfaces is generally good for the pond and provides food for the fish. (Note - There's lotsa products out there that claim to have more surface area than lava rock, or work better, but those claimants are usually selling something more expensive. Lava rock is pretty cheap at garden centers.)

The absolute best filter I have found (after spending major league time and money experimenting) is a lava rock system. Lava rock is very porous (it's so light that some often float until they soak up water enough to sink). All that surface area will get covered with good bacteria to break down the ammonia from fish waste and eats the algae that colors the water green.

Further it makes a dandy mechanical filter as well but that's not its primary function.

We made our filter out of a fifty five gallon plastic drum and a submersible sump pump (1200 gph - $65 at Rickels, $5 at a garage sale). It's pretty easy.. here's how.

1. Cut out the top the drum so it is open.

2. In the bottom, put an 1 1/4" drain with a length of pool hose attached to it. Make sure you use at least 1 1/4" as it makes cleaning a breeze. Fashion a hook or use twine to hold the free end of the hose above the top of the drum. (You could put a valve on the bottom as well but the hose is a lot cheaper and much easier to use.)

3. Put a milk crate inside on the bottom and a grate on top of it. You can make the grate out of heavy plastic coated 1/2" wire mesh. I used a light diffuser from a fluorescent light fixture. (You've seen them, made out of white plastic, 1/2" squares. It's called egg crate.)

4. Put a 1" fitting for the input hose in the side of the drum just below the level of the grate. The space between the grate and the bottom provides a settling area for dirt, etc. before the water percolates up through the lava rock.

5. Put an 1 1/4" discharge fitting near the top of the side of the drum for the filter outlet. You may need 2 depending on your water volume. You might want to leave it 2 or 3" below the very top so that it can build a little pressure if it tries to overflow.

6. Fill the drum with lava rock ($5.35 a cubic foot at a local landscape center) to about 3 or 4" from the bottom of the filter outlet. You'll probably need 4 or 5 bags. (When the drum is filled with water, put water hyacinth or something else fast growing on top of the rock. The roots provide additional filtering and it makes a nice cover.)

(NOTE- I apologize for the hokey diagram below, but it's the best I could do, given the limitations of my imagination.)

1. The floc settlement area, should be at least 2" between the bottom of the discharge pipe and the top of the lava to keep the floc from going into the pond. ("Floc" is matter created by the algae, analogous to feces)

2. The discharge pipe(s), must be a lot larger than the input pipe. The water is coming in under pressure (greater than gravity) and is leaving under gravity. I have two 1-1/4' outlets here. You don't need pipes, you could just cut a hole in the barrel here if you wanted. Pipes worked out much better in my application.

3. The area filled with lava rock . The deeper this is the better, mine is about a third or more of the barrel.

4. The grate the lava rock sits on. You'll have to imagine the milk crate it sits on to hold it off the bottom, it was just beyond me to try to "draw" one in here. There is a small piece of grate in front of the discharge pipes in case some floatable plugs it up. (Been there, emptied my pond when a piece of lava floated up and plugged one and the filter overflowed).

5. The input pipe from the pond. Mine is 1", which is plenty big enough for my 2,000 gph sump pump after going through about 20' of pool hose. Make sure you locate the input JUST BELOW the grate the lava sits on. If you put it too close to the bottom, it will defeat the purpose of the settlement area and keep the dirt stirred up and clog the lava much sooner.

6. The settlement area for heavier pieces of dirt. Mine is about a third of the barrel.

7. The clean-out drain. Mine is 1-1/4". DO NOT use less than 1 1/4" here, even if you are using a small barrel or bucket. Filter flushing is just SO MUCH EASIER, FASTER AND BETTER with a large discharge it is a foolish economy to use anything smaller.

There you go, the filter is done. Whatever you do, use as large a pump as is practical. A rule of thumb I use is to turn the pond over at least once an hour, more if possible. This is NOT cast in stone. You could always start with a much smaller pump. It's been my experience that a great flow is not needed for the bacterial part of the filtration. It is nice to have a large flow for a waterfall though.

My submersible sump pump is inside a small bucket with a grate (egg crate is good) fitted over the top of the pump with a layer of stones (lava rocks work well) on top of the grate to keep fish from swimming through the grate. (Note-I tried matting over the top to provide a pre-filter for the larger stuff so it wouldn't clog my lava too quickly but lost several nice fish because as the matting plugged up, it increased suction around the edges and fish would get sucked in and killed there. - lost a dandy Ryukin that way.)

With the pump inside the bucket, it also provides a measure of protection for your fish and plants two ways:

1. In case of a major leak outside the pond (broken hose, etc.) as the water level won't go below the height of the bucket. (This has happened to me a couple times, once with a busted hose and another time when a piece of lava floated up and plugged a discharge pipe - got a screen over them now. )

2. Protection from fish and plants being sucked into the pump (been there too - hence the large stones instead of matting).

When your water flow slows down (or more often) drop the drain hose of the main filter and flush the lava rock from the top until the water runs clean. I discharge into a garden area, good fertilizer you know. Only takes a couple minutes.

The larger your filter(s) the less often you'll have to clean it. And generally it doesn't take any longer to clean a large one than a small one. Some of the guys have made theirs out of 5-15 gallon buckets but they're cleaning once a week or more. Mine can go weeks/months at time, but I usually drop the drain hose every week or so to keep it flushed out. With the large drain, it's a snap.

It's important that your cleaning process be a simple one. If it's a pita to do (say has a small drain that doesn't allow for easy flushing and takes forever to drain), it won't get done as often. What happens then is sshtuff will get packed in the lava rock so tight, you'll have to remove the rock to clean it. And that's a real pita.

If you see the water "channeling" up through the lava in places, you can be pretty sure it's starting to get plugged. Don't put off cleaning it if it channels. It isn't working well and can only plug harder making it more difficult to flush.

And there's no rule says you have to use a barrel either. One local ponder has a children's plastic pool made using the same principle as the barrel filter and it works really well.

I wish!

An important fact to remember is that as water warms it rapidly loses its capacity to hold oxygen. I don't know the actual numbers but it is dramatic, almost logarithmic, something like holding 2 or 3 times oxygen as much at 50 degrees as it does at 60 degrees. And the warmer the water gets, the less oxygen it holds, so aeration is important (even critical), especially if you're like me and like high populations of fish.

My pump is located at one end of the pond and discharges down a rock wall built of flat stones into the pond at the other end. If you do that, you'll need to put a liner behind and underneath the stones to prevent leakage. (or cement them in place, or ....).

(Note- You may find the waterfall to be a water hog and lose water due to either splashing outside the confines of the pond or leaking. I have/had both those problems. If it happens to you, make sure you stay on the good side of your son because it's a lot of work taking out those rocks to relay the liner underneath or whatever.)

The water gets thoroughly aerated and re-oxygenated falling down the 4' high wall of rocks. This is healthy for the fish and is another form of filtration (oxidation) as well. Our wall gets lots of sun and what happens is that algae builds up on the rocks and seeds from our hanging impatiens drop and bloom in the algae (even more filtration. Looks pretty neat too).

You could also locate the filter some distance away and build a stream meandering back to the pond. If you do that, make sure to put plenty rocks in the stream bed to disrupt the flow to get better aeration.

For a really rough gauge, you can figure to get 25-30 square feet of coverage from a pallet of flat landscape rocks (like slate). 'Course you could get a lot more or a lot less too, but it's a ballpark.

Other Stuff

Locate your pool in sunlight if possible, the water lilies will flower much better in direct sunlight. The pond inhabitants (fish & plants) are just so much more attractive in the sun too. Positively sparkle. Be aware of trees - leaves gotta fall somewhere. You probably oughtta have the sides a little higher than the surrounding land so as not to get runoff (probably contaminated with lawn fertilizers and herbicides) into the pond.

You might want to taper the sides of your pool to provide a slope for plants and stones for a more natural appearance. Or you could put a step (6"- 12") from the top to hold potted plants. Or ....

If you use a waterfall or put rocks around the edges of the pool, extend the rocks 6-12" below the surface. They'll provide lots of little caves and crannies for the fish to hide and play in. A couple of my friends have had baby goldfish and shubunkins hatch in their ponds and I never did. They had rocks and I didn't and I think that was probably the reason. (I got 'em now baby.)

(It's been my experience, and I've been through it several times, that it takes a year for a pond to "develop" and start to look like, well, a pond.)

Otherwise almost any member of the carp family will do well. Koi, shubunkins, ruyakins, and comets will all survive cold winters nicely. Winter mortality is usually well under 10% and is often 0%. I havem all in my pond and they do well.

If you're into the wine tasting scene ("Firm but not over powering", "Lascivious but not obscene") look into koi. There are some pretty "exciting" lineages there and some very nice looking fish. Not my cup of tea though.

If you live in a temperate area where the water temp doesn't go much below 50-60 degrees (he said covetously), you can use pretty much any kind of tropical fish. I'd love to have some angelfish in my pond. I'm in New Jersey shore where the temperature usually ranges from the teens to the 90's every year and we've had even more extremes so exotic stuff is out (at least the expensive ones).

Put some tadpoles in the spring. It's fun to watch them develop into frogs. The frogs will winter okay if they can burrow into the bottom somewhere. Ours don't usually last that long. Iron Ernie eventually getsem. Ernie is a cat. The symbol for iron is Fe which stands for Frog Eater. Hence .... Iron Ernie. Oh well, not funny I know but... my cat and my home page.

Got a quart of killies and a few dozen shiners too (bait fish from the local tackle shop) this year. Dunno how they'll survive the winter yet, my first time with them. I don't think I'll put them in again though, they're aggressive eaters and the rest of the fish consequently get less opportunities. Besides I saw them eating my guppies, a real NO NO. (Note after a full year there's still a half dozen or so shiners still kicking, worse luck. A dozen or so minnows too. First time through the winter for them. No killies though. )

Another advantage with 10 centers is that you can over populate, they will find their own balance and you won't be out big bucks. Nothing hurts me more than to lose a $10 or $20 fish.

As soon as the water warms up enough (60's), I usually put a couple bucks worth of feeder guppies in. They thrive and multiply like rabbits all summer and into the fall (except so far this year ('97) the damn shiners ate them) Cold water gets em though. Feeder minnows too. They add variety and interest.

(If you have small fish and put in a small channel catfish, you'll end up with a huge channel cat and a lot less fewer fish. That's what happened to me this summer. I always thought they were vegetarian but I found out that when they reach a certain size, .... well scratch all my minnows, guppies, feeder goldies, etc.)

I feed my boys a lot. Any time I don't see anymore Friskies floating, I throw in another handful. Winter time too though they don't seem to eat near as much. I've heard a lot of claims about only feeding once or twice a day and then only as much as they'll eat in 2 or 5 minutes but I don't subscribe to it (though I do in my Salt Water tank). Under that theory, the big dogs get to eat the most and the little guys hardly get anything. My way they all get as much as they want

(I have so much filtration I don't have to worry about overfeeding {grin}).

Besides the Friskies, I have a small plastic bucket (about 2 qts) filled with a mixture of: a cup of Tetramin Fish Flakes, a handful of Friskies, a couple handfuls of some puppy dog food my daughter gave me that looks like gray Cheerios, a couple handsful of Tetramin Floating Pond Sticks. I mix it up a little and the flakes get ground into a fine powder. The Friskies and pond sticks float, the "cheerios" sink and the flakes do both. That way all sizes get something and a good rich varied diet. They get a handful of this once or twice a day or more (whenever I think about it or just want to see them swarming). (It isn't necessary to be so anal, I'm retired and just don't have a whole hellava lot else to do.)

I have a secondary behind my waterfall that's essentially a tray 6' x 7' x 12" deep. And has about 1,000 lbs of fine gravel in it leaving an average water depth of 5-6".

The top of the tray has 2" x 2" on three sides leaving the waterfall side 2" lower providing a wide discharge to spread over the rocks. While we were doing it, I figured I might just as well add more filtration, so I put a 6" baffle (a 1 x 6) across the top of the tray about a foot away from the discharge wall. The baffle is raised off the bottom 6", forcing the water to go underneath it. The space between the baffle and the discharge wall is filled with lava rock (put the lava in before you put the gravel in). The gravel is then sloped up to the top of the baffle. This forces the water to go through at least 6" of gravel (which provides both bacterial and mechanical filtration) before it travels through the lava rock (serious bacterial filtration) and down the waterfall (aeration and oxygenation filtration).

Due to a request, here's a crude drawing for a baffle type filter.

• The top of tray is 2" above the normal water level.

• The top of the baffle which is an inch below the top of the tray and extends down to about 3" from the bottom .

• (## represents the gravel and the @@ represent the lava rock. Caution- don't use too fine a gravel or it will plug quickly.

(Note- if you use a baffle system to force the water through the gravel, MAKE SURE the top of the baffle is below the height of the 2" X 2"s or when/if the gravel gets plugged with dirt, the water will flow over the tray sides instead of down the waterfall - The voice of rueful experience here .)

To clean the gravel, all I do is shut the pump off and rig up a siphon (using large diameter pool hose), stir the gravel with a board and a garden hose. The dirt floats to the top and is siphoned out. I only had to clean it once last summer so it wasn't too bad.

With the tray setup, I probably don't need the 55 gallon lava rock drum but I left it in the system anyway (remember you can only have too little filtration). My pond (about 1800 gallons total) stays so clear you can read a magazine on the bottom 30" deep.

Essentially they are undergravel filters just like those used in aquariums. We took 2 pond lengths of 1 1/4" PVC pipe and drilled them full of 3/8" holes and laid them on the pond bottom, each with an elbow on one end pointing up and a piece of pipe long enough to be about 6" below the water surface when the pond is full.

Synthetic matting was laid on top of the pipes and the gravel on top of the matting. (I got my matting at a local pond supply place but you can use almost anything that's water permeable.)

I prefer matting because it adds just that much more area for bacteria to grow but you could even use plastic or nylon window screening on top of a more rigid plastic mesh (just not a metal that will eventually rust or corrode). The reason for the rigid mesh is that you don't want the screening to wrap around the pipe when you put the gravel on top. It's okay if it "tents" over the pipe, just so it doesn't wrap tightly. The object is to increase the "draw" area as much as possible.

From your local aquarium store, pick up a "power head" for each pipe. I got mine mail order from That Fish Place (800-733-3829) for $17 apiece. 300 gph each (NOT larger - don't want too much suction through the gravel). Power heads will fit nicely on top and inside of 1" & 1 1/4 " pipes. I have my pipes cut so the tops of the pumps are 2 or 3 inches below the surface. They provide an almost imperceptible surface current providing an even greater oxygen interface exchange.

They were cheap and easy to put in (even if unnecessary overkill) so why not do it (he thought)? If you stick the pipes in when you're building it, it's almost no additional work. You can add the pumps anytime. You could even use aquarium air stones instead of power heads to pump the water as well (might even be cheaper and would provide even further aeration).

(Note - after a full year with the undergravel filters, I can't recommend them highly enough. I let them run all winter (moving water normally won't freeze) after I had to shut the waterfall off (ice). Pond stayed crystal clear and they haven't plugged up yet. I think the reason they don't plug is that such a *relatively* small amount of water is being drawn from such a large area (wide matting over the long holey pipes) there isn't enough suction anywhere for plug it up. I'd even bet I could get by with just them and no lava filter for biological filtering.

I'm really pleased with them and strongly recommend them to anybody building a new pond. They are so easy to make and very cheap to run (30 watts per pump - maybe $1.50 a month for electricity).

Mine have been working over a year now, even let them run through the winter when the pond froze over (on top), and the gravel hasn't plugged up. The object is there is such a large draw area for such a small volume of water there isn't enough suction to plug the gravel tightly.)

They don't really give any mechanical filtration so I still have to use my lava filter for that. Want the waterfall anyway, but It's nice to know I don't NEED it. Go on vacation and not worry about leaks, splashing, etc.

There are chemical additives to keep the water clear but I stay away from them. If they kill the algae (a living organism) then what do they do to plants and fish? The closest I come to that is to put 10 lbs of sea salt ( NOT NOT NOT table salt) in once a year. It's supposed, and seems, to be good for the fish. (I recently noticed a couple fish getting lesions and was out of Sea Salt (it's pretty expensive, around a buck a pound) and saw some bags of "natural" salt (made from evaporated water, not mined like rock salt) at Rickles for under a cent a lb (40lb bag for $3.50) so I gave it a try. I put a bag in and the lesions cleared up after a couple weeks.)

I haven't been real specific in a lot of places here figuring you have common sense and can fill in the gaps yourself. There are no hard and fast rules other than not having a leaky liner. And even that rule can be bypassed if you have a ready supply of cheap water . (Though I think recycled water is probably healthier.)

There IS one rule you shouldn't ignore, a ground fault interrupt outlet(s) for your electrical stuff. You'll be using electricity to power stuff, some of it immersed in water and should you ever get a short, well .... better safe than sorry.

However you do it, as soon as you're finished, you'll wish you had done it another way (if you're a true ponder) and wish you had/hadn't listened to so and so. The ponders I know around here are pretty much do-it-yourselfers and consequently come up with a lot of individualization, innovation and adaptation . For example, the latest addition bought a large stainless steel tank at an auction (talk about a lifetime liner guarantee).

We all get a great deal of satisfaction from our ponds and help each other out, even knowing the other might improve past the rest of us, prompting a whole new round of "The next time I'm gonna ...."

Due to popular demand, I finally got a scanner ( Father's Day, Birthday, Anniversary & Christmas presents all in one, so I've been told by my wife.) Anyway click here for the long awaited pictures.

Letters and Tips from other Ponders and visitors to this page.
If you have any questions, you are likely to find the answers (in so far as I have any) here.

1997 End of Season Report A report on how I fared the summer.

Pond Links A fairly comprehensive list of Pond related sites.

USDA Minimum Temperature Map For comparison, my Pond is in Zone 6.

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