This is the second ‘box pond’ I’ve built. The first was great, but the only filter was the small submersible pump. I also didn’t like the pump sitting on the bottom, with the wire hanging over the edge. The bottom was covered with a large-sized gravel substrate. This gathered a lot of fish excrement, uneaten food, and general dirt and waste-matter. The result was an inadequate filter, and regular cleanouts. The cleanouts were difficult, too. I had no way of draining the pond, so I had to siphon it and then scoop the remainder out. This meant putting the fish in buckets and wasting half a day getting dirty. I decided to design a ‘box pond’ fully fitted with filter, multiple drainage points, and no pumps and wires on display. One thing the first pond had that the new one doesn’t, is the ‘upside-down fish tank’ you can see it below on the back-right side corner. It was cool to watch the fish swim up inside it. Great way of viewing your pond fish, which are normally only seen from the rather generic birds eye view.
- This time I didn’t want PVC liner. I built a sturdy wooden frame, boxed the inside with 5mm (too thin in hindsight) plywood, then painted the inside with AquaTite [a water based, fish-friendly waterproofing paint from Bondall]. The thin plywood meant the bottom flexed too much (even for AquaTite ‘flexible waterproofing membrane’) so when i filled it the weight of the water cracked the seals. I got round this by putting a layer of AQUAgard [this is a cement based waterproofing by an Indonesian company called PT.Inter Aneka Lestari Kimia]. this layer at the bottom is about an inch thick and dried like cement, so the movement of the base was eliminated.
- The next step was filtration. In the first pond I had relied on the small foam sponge filter that is fitted inside the intake cap of the submersible pond pumps you get in the store. I wanted to filter out the fish waste, leaves, and uneaten food before it got to the pump. I originally planned an elaborate 6″ pipe system; starting with a swirl filter, then a section with brushes, finally regular filter-pads. This proved too ambitious and with limited space in the filter section, I decided to go for the design below.