I have a roughly 600 gallon pond; 10'x6' and 30" at it's deepest point. It's about a year old at this point and has been working great aside from some algae issues. I had some green water last summer when the temps were high (95F average summer temp), and have been battling string/hair algae this Spring. All of this points to an excess of nitrate/nitrite in the water especially in the Spring when none of the plants are growing quickly and taking up those nutrients.
I've always wanted to build a bog filter not only for it's filtering capability, but also for some extra space to add some marginal plants. And if it helps soak up some of those excess nutrients then that is a fantastic benefit. In the pictures you can see the general layout of the pond: skimmer filter with a 2,000gph pump that flows first into a All Clear G2 filter, then into a small waterfall weir. Both the skimmer and the weir have some sponge/filter media for mechanical filtration.
What I'm thinking is to add a "Y" splitter after the All Clear G2 and direct the flow to both the bog and waterfall. As for construction of the bog, I have an ideal space that's largely unused to the right of the pond. It already has an 18" retaining wall and roughly a triangular 9'x4' area. My plan is to take a 3'x3' area and dig down for a total depth of 24" for the bog filter. I'll use 2-3" PVC in an "H" shape in the bottom and cover with smallish river rock in the bottom 4" and then the rest pea gravel. I also plan to slope the bog filter down and have a large cleanout snorkel, although I'm not sure I'll need it.
I'm still unsure if I want to have a waterfall as the output of the bog filter, or hide a PVC outlet somewhere among the rocks on the side. Or perhaps construct a short stream bed that the goldfish can swim up into. I plan to have the edge of the bog 4-6" above the pond level and overlap the bog liner down into the pond. I'm hopeful this is enough to avoid any wicking.
I'm interested to hear your ideas, advice, horror stories and whatever about bog filters. Cheers!
I've always wanted to build a bog filter not only for it's filtering capability, but also for some extra space to add some marginal plants. And if it helps soak up some of those excess nutrients then that is a fantastic benefit. In the pictures you can see the general layout of the pond: skimmer filter with a 2,000gph pump that flows first into a All Clear G2 filter, then into a small waterfall weir. Both the skimmer and the weir have some sponge/filter media for mechanical filtration.
What I'm thinking is to add a "Y" splitter after the All Clear G2 and direct the flow to both the bog and waterfall. As for construction of the bog, I have an ideal space that's largely unused to the right of the pond. It already has an 18" retaining wall and roughly a triangular 9'x4' area. My plan is to take a 3'x3' area and dig down for a total depth of 24" for the bog filter. I'll use 2-3" PVC in an "H" shape in the bottom and cover with smallish river rock in the bottom 4" and then the rest pea gravel. I also plan to slope the bog filter down and have a large cleanout snorkel, although I'm not sure I'll need it.
I'm still unsure if I want to have a waterfall as the output of the bog filter, or hide a PVC outlet somewhere among the rocks on the side. Or perhaps construct a short stream bed that the goldfish can swim up into. I plan to have the edge of the bog 4-6" above the pond level and overlap the bog liner down into the pond. I'm hopeful this is enough to avoid any wicking.
I'm interested to hear your ideas, advice, horror stories and whatever about bog filters. Cheers!
