How To Properly Conceal a Biofilter

So, there’s been a lot of good, sensible talk out there about how hard it is to hide a giant plastic biofilter at the top of the stream you’re building. In all fairness, when it’s just sitting there, exposed, before rocking around it, hiding a sizeable biofilter can seem near impossible. But there are simple, solid techniques to hide those big black boxes, and some compelling arguments in favor of using biofilters to start streams.

 

Advantages

The advantages of having an upflow biofilter are well-known and pretty convincing. In general, they hold an impressive amount of filtration that not only removes suspended solids but provides surface area for beneficial bacteria that consume ammonia and nitrites. Their position at the top of an elevated stream usually means they can be plumbed with a drain valve, so they can be rinsed or backwashed easily. More complete cleaning may need to be done only once or twice a year, because of the way upflow biofilters work. The pump forces water up through the filter media under pressure, so the media tends not to clog easily; although the water may channel around the media, it won’t stop flowing. Finally, the ability to securely attach both the plumbing and the liner to the filter to start the initial waterfall has eliminated the most common leakage point in stream construction.

ATLANTIC’S BF1600 COMPLETELY HIDDEN BY ROCKS

technique

SETTING THE FILTERFALLS INTO, RATHER THAN ON TOP OF THE ELEVATED AREA

Hiding a well-designed biofilter is primarily a matter of setting it into, rather than on top of, the elevated area. This is typically formed by mounding the excavated soil from the pond or reservoir. After the filter is properly set, then it’s a matter of simple rock placement. In nature, a stream cuts its way down in the surrounding land; waterfalls form as the flowing water scours out a pocket in softer soil or rock behind a hard surface. In theory, we want to bury the biofalls behind that ‘hard surface’, the rock or stone the water will flow over. What often happens instead? The biofalls is placed on the ground and soil is heaped around it up to the top of the box, then rocked, to form the utterly unnatural ‘water volcano’ we all love to hate.

BF2600 FILTERFALLS HIDDEN UNDER ROCKS

It’s a simple mistake, and just as simple to avoid. I prefer to mound and tamp the soil first, then carve out a space for the filter, then plumb to the front of the filter, but the box can be set and plumbed first – to each his own style. The point is, the soil has to end up higher than the top of the box, so the water flows out from about two-thirds up on the slope. If that requires digging the filter down, so be it. Then, I excavate the tamped soil away from the front of the filter, cutting a vertical wall the width of the filter to either side. I dig down until I reach the level of the bottom of the splash pool at the base of the falls. Then I attach the liner, leaving a couple of loose folds below the lip, to allow for settling and adjustment. Now I can start the stream by setting rock to create the first fall.

The idea is that building the waterfall is the objective, not hiding the filter. That will come by itself if I accomplish three tasks. First, I need two ‘shoulder’ rocks on either side that are taller than the filter, set to cover the ends of the spillway or opening of the filter. Next, I set a spill rock, or rocks, between the shoulder rocks up to the height of the spillway.

Now I need to fill between the rock and the filter to stabilize the falls. I usually have the space behind the shoulder rocks to push soil in behind the liner. If not, I’ll just fill any void on top of the liner with rounded stone. Either way, I’ll foam between the liner and the rocks, sealing the space so all the water goes over rather than around the spill rocks. As a finishing touch, I set small, flat rock on the ledges and grate inside the filter to finish hiding it.

Sounds simple, and it is. Working ‘backwards’ on the falls instead of focusing on hiding the filter actually hides it better. Couple of quick recommendations:

  1. Get the largest filter you can fit. The larger the filter is, the easier to hide, because the stones set on the grate or ledge can be larger without compromising the flow or forcing water up over the sides. Of course, having more media and settling volume can only help as the pond matures and organic loads increase.
  2. Tilt the filter forwards a couple of degrees, on a well-tamped base. Nothing worse than having a filter settle and water leak out over one side or the back.
  3. I always plumb the filter with a cleaning drain, and use Matala semi-rigid mats, to allow for fast periodic backwashing. This reduces the frequency of tearing the filter apart for major cleanings to once every couple of years.

If you have any questions or tricks to concealing a biofilter please comment below.

 

 

Quick Tips – Waterfall Construction

In the world of water features, there are many different tactics that contractors and homeowners use to approach building a water feature. Over the years I have encountered a variety of construction methods water features are built and through my experience have put together a list of tips that I think will help you create a natural looking water feature.

Use different sized rocks to achieve a more natural looking waterfall. But let’s be honest, when building these features moving heavy rocks can be quite the challenge.

Tip #1.

Try cutting a piece of underlayment (commonly known as geotextile fabric) large enough to hold the rock you are trying place and use it as a sling. The corners will act as handles for you to hold on to. Because the fabric is very strong it can handle the weight of heavier rocks.

 Another option to move heavy rocks by hand is to use tow straps or tie down straps. This method can be used with heavier rocks and will require more than two people to move the size rock you are working with.

If you are using large boulder and neither of the two options prove useful, you may need the help of larger equipment.

**You do not want to hurt yourself trying to move these rocks, equipment can be rented on a day to day basis at your local rental yard.

While you are placing your rocks keep in mind that you are also creating a place for water to flow. When creating your waterfall or streambed you will notice gaps forming around and behind the rocks that you have placed. Once you turn on your pump water will flow into these gaps instead of flowing down your streambed causing you to lose some of the visual effects of your stream or waterfall.  In order to avoid this, these gaps should be filled.

Tip #2.

When filling the gaps, a mortar or cement type mix can be used but this method is highly susceptible to cracking and movement. Another option is to use expandable foam, the foam will not crack or move and can fill large or small gaps in the rock placement. Typically foam is grey in color so that it will blend with most rock colors. Waterfall foam cans from Atlantic are available in two sizes – a 12 ounce can with a straw applicator or a 29 ounce can, which requires using a professional foam gun.

I highly recommend the professional foam gun if you build multiple water features during the season.

For the average one or two builds a year, the DIY 12 ounce can works great. To save on the use of foam you will only need to apply the foam in the locations that water is flowing over.

Please be sure to wear gloves and protective eyewear when handling the foam as it is very difficult to remove.

Tip #3.

A great technique to disguise the foam that you used to fill in the gaps is by covering it with smaller stones and/or gravel. You can also add a small amount of sand over the foam before it is completely dry to disguise the foam to look more like a rock.

Make sure you give the foam time to cure before you turn your waterfall on. Once the waterfall has been turned on you can add more foam to push the water in the direction you prefer at any time.

Remember this is a foam product and is not glue or a patch product for leaks. It is only used to direct the flow of water.

 

Hopefully, these tips will help save you some time and frustration (as well as your back!) and keep your water flowing in the right direction! If you have any tips of your own, please feel free to comment below.

 

About the Author:
Jim is the National Sales Manager for Atlantic Water Gardens.
JIM CHUBB

Jim has 26+ years of sales experience and 16+ years in the water garden industry.

 

Tools That Don’t Suck – Cordless (Liner) Trimmer

As water feature installers, my sons and I are used to hard, dirty, sometimes dangerous work. We enjoy what we do, whether it’s digging ponds, plumbing pumps, rolling boulders or tweaking waterfalls, but we also value anything that helps make the work easier or more fun. We’re always looking for tools, apps or gadgets that save time & effort, eliminate stress, add to our comfort on the job or are just fun to use. Often a buddy will turn us on to one. I’d like to return the favor by passing our favorite Tools That Don’t Suck along to you.

Cordless (Liner) Trimmer

TrimmerThis first tool makes the nasty job of trimming liner and underlayment easier and much safer. Most of us have had to trim wet, bunched up, sand- and mud-laden underlayment and liners. It’s a dangerous chore. Razor knives that so easily cut clean fabric in the shop dull in minutes in the field, requiring new blades constantly (until you run out). There’s always the risk of cutting too close or through a hidden fold (or yourself) while hacking away. (And let’s not even mention where the dull-but-dangerous-used-blades-that-should-always-be-safely-disposed-of turn up.)

My wife Susan, who is always looking out for me and her boys, saw this little trimmer advertised for scrapbookers. She actually thought it might work for us! I laughed at the “toy” when it arrived. I don’t laugh at this tool anymore. I have since apologized to Susan. Many times. (She likes that.)

Skil TrimmerThe original trimmer shown is 4 years old and has gone through hell. It ain’t fast, but it still chews through muddy, sandy liner and underlayment for hours on a charge, though I’m not sure exactly how many. In the field, trimming in 10 minute bursts every hour or two, it doesn’t run out for a couple of days, very forgiving for when we forget to charge it overnight. The octagonal blade with its 8 corners almost self-feeds through a single layer of liner up to 60 mil or 8oz fabric with minimal effort, and it continually sharpens as it spins. One last thing, for anyone with employees (or sons, or an aversion to seeing their own blood) – it’s almost impossible to cut
yourself.

Skil discontinued the model shown, but there are a number of similar trimmers out there, many around $45. At that price, we can afford to test them for the day that Old Red finally dies. Give these cordless trimmers a try; I think you’ll find this is one Tool That Don’t Suck. Thanks, Sue!

**UPDATE

QUICK CORRECTION AND THANK YOU – out to the The Pond Gnome Paul Holdeman for being the REAL source for the nifty little Liner Cutter featured in the last blog. Although Susan had purchased them for me and the boys on a scrapbooking site, Paul showed it to her at a charity build he graciously donated his and his crew’s time and tools for at the Virginia C. Piper Cancer Center of Phoenix in 2014. Thanks Paul!!! It was a pleasure working with you!

 


 About the Author:
Demi is the Direct of Product Information for Atlantic Water GardensDEMI FORTUNA

Demi has been in water garden construction since 1986. As Atlantic’s Director of Product Information, if he’s not building water features, he’s writing or talking about them. If you have a design or construction question, he’s the one to ask.