Best Practices | Glass-Paneled, Raised-Pond Construction

It’s like watching Koi TV from your living room or patio!

In early 2018, I received a call from Anthony in Aliso Viejo, California, who needed assistance designing his pond. Anthony was in construction and had acquired some glass panels. He wanted to build a pond with windows on the sides. Anthony and his wife Linda’s backyard was small, so a raised pond would be a good idea. However, this raised pond would have to be several feet tall.

Anthony sent me several pictures of the concreted area he wanted to build on just in front of the back wall. He had three panels — two long ones and one shorter one. The long ones were 6 ½ feet, and the short one was 4 ½ feet. Anthony decided at first to only use the two long ones on the front side. This would make the pond about 14 feet long by 5 feet wide at a depth of 3 ½ feet. The space he had to work with, plus filtration volume, would give him a pond just under 2,000 gallons.

With that information, I worked up a 3-D drawing he could start with and supplied the equipment. In the beginning he didn’t want to cut into the concrete floor any more than he had to, but after receiving the equipment and looking at the retro-drain, he decided to cut the floor for an in-floor, 3-inch drain. This was a good change. I supplied a Waterway Renegade skimmer with the large basket for the in-wall skimmer and two LWS in-floor air diffuser cups with 5-inch diffusers cut into the concrete floor for aeration on a timer.

The two air diffusers are supplied by an air pump he already had. The 3-inch bottom drain flows to a 55-gallon drum radial separator sitting just outside the left wall. A WLim Wave I 1/6 Horsepower pump pulls from the 3-inch bottom drain through the radial separator and from the skimmer pushing the water to the opposite end, where the filtration was to be located.

Splitting the Spills

hardscape pond koi

The window rails are in, and the surface is parged and the surface was coated with Polyurea, ready for glass.

The pond was to have three spills: one on the right end and two along the back wall. Having only spills as returns meant there wouldn’t be enough turbination for a good dissolved-oxygen content. To correct this, I split up the biofiltration into two tanks, one as an upflow sand and gravel filter for fines polishing, and the other as an air-driven dilution reactor (ADDR) for oxygenation, powered by a Medo 60-lpm air pump. The right spill would flow from the sand and gravel filter, and the two on the back wall would flow from the dilution reactor. An aerated biofilter can flow more volume than an equally sized trapping filter, such as the sand and gravel filter. Two return fittings were installed in the end wall to bypass any excess volume without restricting the pump. The 57-watt LWS ultraviolet light is mounted inside the sand and gravel filter in a down-flow configuration for easier mounting and hiding.

Anthony made a few good changes along the way in addition to the drain swap. He moved the prefilter and pump pad farther away and closer to the fence on the left side. This gave him room to install the third shorter piece of glass, giving him a viewing opportunity from the left end. He built the end wall and formed it at a 45-degree angle, which created an aesthetically pleasing shape against his back wall.

3-D drawing waterscape pond

The initial 3-D drawing for the project are shown above with plumbing layouts.

The walls were formed and poured in place by Anthony’s crew, who did an amazing job. Paul Parszik of Artisan Aquatics was called in to apply the polyurea and advise on the window installation. Paul is one of the best in the business at preparing window channels and sealing them to the wall construction. The windows were set in welded, U-shaped L-channels bolted to the concrete, and the polyurea was applied over the concrete and into the channel.

nighttime hardscape pond

What a light show!

Prior to the polyurea application, the surface must be parged with something polyurea likes chemically. Paul has requested Bond-Kote in the past, but that product has recently become unavailable. Lately he’s been using Proline Coating’s ProSurfacer, and it works well with the polyurea. Once the polyurea was applied, the glass panels were sealed in place with Dowsil 795, formerly Dow Corning 795, which is an architectural-grade silicone sealant. The glass panels are ¾-inch thick Starfire lead-free tempered glass. Starfire glass is crystal clear and offers amazing brilliance with little or no discoloration.

One LWS LED light fitting is installed in the right side with a Melody Blanco LED 12 Volt light. Anthony chose CMP Brilliant Wonder LED lighted waterfall spills for the sheer descents.

The glass-paneled raised pond gives Anthony and Linda’s small backyard more depth, opening it up with a beautiful view. When done correctly, window ponds can be an elegant pleasure in any backyard space.

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