Sizing the purification pond to the pool
Zero-discharge land-based circulating system: a 400 m³ canvas pool body suits a purification pond of about 0.33 ha at 2 m depth — too large wastes breeding area, too small cleans poorly (small ponds should be 3–4 m deep).
Choosing pond diameter by stage of growth
Selecting the pond: 3–5 m diameter for fry; 6–10 m for grow-out fish (over 10 m, sewage discharge weakens; fine for storage). Galvanized canvas ponds are economical and last about 8 years; iron-frame canvas ponds are easier to install/disassemble and suit short leases.
Cone bottom and discharge design
Sewage design: use a pot-shaped cone bottom at about 10:1 radius-to-depth ratio — a 6 m pond with a 30 cm cone, a 10 m pond with a 50 cm cone. A 6 m pond uses a 110 mm discharge pipe; a 10 m pond uses 160 mm. A middle sleeve or drilled boundary pipe works well; a U-shaped pipe controls the water level, discharging directly or through a central line to the purification pond.
Matching pumps and blowers
Equipment matching: a 3.0 kW submersible supply pump (with standby), 160 mm supply line and a 75 mm switchable inlet; two Roots blowers (2.2 kW and 3.0 kW) as independent aeration systems that can run separately or together, with a 2.2 kW motor as standby.
The pond structure itself is on the canvas fish pond page.
Frequently asked questions
Q: How big should the purification pond be for a 400 m³ pool? A: About 0.33 ha at 2 m depth. Too large wastes breeding area and too small cleans poorly, and small ponds should be 3–4 m deep.
Q: Which pond diameter suits which stage of growth? A: 3–5 m for fry and 6–10 m for grow-out fish. Above 10 m the sewage discharge weakens, so the larger sizes are fine for storage but not for grow-out.
Q: What cone bottom and discharge sizes are used? A: A pot-shaped cone bottom at about a 10:1 radius-to-depth ratio — a 6 m pond with a 30 cm cone, a 10 m pond with a 50 cm cone. The 6 m pond takes a 110 mm discharge pipe and the 10 m pond a 160 mm one.
Q: How are pumps and blowers matched to the pool? A: A 3.0 kW submersible supply pump with standby, a 160 mm supply line and a 75 mm switchable inlet; and two Roots blowers (2.2 kW and 3.0 kW) as independent aeration systems that can run separately or together, with a 2.2 kW motor as standby.
