My brain remembered 25%, so a little smaller, and surface area not water volume.
My bog is over sized, but I wanted the plant area. Currently zero algae growth, will be interesting to see how well it does this summer.
I put in day lilies, their growth is way ahead of the dirt planted day lilies in our yard. I like the statement a pound of bog removes a pound of algae, our bog is 2800 lbs so technically we can remove 2800 lbs of algae.
Not my typing..........lol: The following is some info on bogs.
Basic Bog Filter construction
• Bog Filter surface area should be no less than 10% the surface area of the pond, up to 20% or more if you have a large fish load, and space permits.
• Bog Filter should be approximately 12 inches deep.
• Water should enter from under the gravel
Wetland or bog filters are best constructed in an up flow design which reduces clogging and facilitates easy cleaning. Bio-Mass is key ~ A pound of bog is required to prevent a pound of algae. Plants should be selected that actively grow at different times, that root to different depths and that have different plant structures.
Excellent Plants for the Bog may include:
Arrowhead Sagitaria (zone 4-6) Summer Bloomer. Bulbing root system stores(nitrogen, potassium & phosphorous)
Canna (zone 8-10) Summer Bloomer. A bog’s best friend. This plant is a biomass factory and has amazing beauty and structure. A heavy feeder on (nitrogen, potassium & phosphorous) from April through September.
Cattails (zone 3-5) Summer Bloomer. are vigorous growers and have deep roots.
Creeping Jenny (zone 5) Spring Bloomer.
Daylily - Spring through Summer Bloomer. Surprisingly, water is the best fertilizer for daylilies. They are an excellent nutrient feeder and grow well in the shallow areas of a bog garden. Daylily come in a variety of colors and blooming times for a long lasting color in your garden.
Eyed Grass (Yellow & Blue) (zones 5-7) Spring Bloomer.
Iris - (zones 4-6) Summer Bloomers.
Common water iris. (Louisiana Iris) Great variety in colors and styles. Plant habit is spreading and untidy appearance.
Japanese variegated water iris is a strong grower late spring through fall. Iris are good at removing both nitrogen and phosphorous.
Siberian Iris are preferred for their strong, clumping habit. Most growth spring and summer but use potassium and phosphorous in summer and fall for energy storage for next year’s bloom.
Kaffir Lily (zone 7) Fall Bloomer. A bulbing lily with watermelon red flowers. Grows in cooler temps of spring and fall. Small top growth controlled.
Lobelia Cardinalis (zones 5-7) Fall Bloomer. Beautiful late summer bloom. Nice color diversity. Heavy potassium user.
Marsh Marigold (zones 2-4) Spring Bloomer. A fast growing cool temperature plant. Begins growing very early in spring producing flowers by early March and continues through April, often re-blooms in the fall when weather cools. Medium root depth and actively feeds when most plants are dormant.
Pickerel Rush (zone 3-6) Summer Bloomer. Strong summer growth and bloom. A spreading habit with a shallow root system. A strong feeder on the total nutrient system. Blue Pickerel Rush is very hardy in our area, with a long bloom season.
Rain Lily (zone 6) Fall Bloomer. Late summer and fall grower. This bulb plant has a small controlled top growth but a dense vigorous root system with storage bulbs. Strong user of phosphorous and potassium.
Rush - Variegated Striped Rush (zone 5-6) Summer Bloomer. Evergreen and continues to grow almost year-round strongest growth in summer. Roots are shallow and need oxygen. Open habit allows for under story growth.but has a large vigorous root system feeding its bulbs. Very
Slough Sedge (zone 4) Very prolific, yet clumping. Grows to 5’ high in bogs. Deep rooting habit. Bio-mass. Strong user of potassium, sulfur, calcium and sodium. Somewhat salt resistant.
Society Garlic (zone 7) Summer Bloomer. Strong summer growth. Love phosphorous.
Star Grass (zone 7) Summer Bloomer. Very controlled, medium root depth, summer fall growth. Grasses are strong feeders of potassium and sulfur.
Thalia (zone 6) Summer Bloomer. Very deep rooted. Open stem structure allows for very diverse under story growth. Summer blooming. Large storage roots.
Water Forget-Me-Not (zone 3) Spring Bloomer. Vigorous low grower. Shallow rooted. Easily pruned. Blooms from March through October.
Yellow Monkey Flower (zone 6) Spring Bloomer. Early spring growth and bloom. Deep root system.
cheers.