DIY Biological Filter for Small Pea-Soup Pond

8x4 ft pond (14–30" deep), NW Indiana, afternoon sun, grass plant, 4 comets, fake lily, pump 24/7. Pea soup water. Asks DIY biofilter instructions.

Simple DIY Biofilter Build

1. Container: Sturdy plastic tote/barrel (20–50 gal).
2. Pump at bottom.
3. Layer 1: Lava rock (covers pump).
4. Layer 2: Filter floss/polyester quilt batting.
5. Layer 3: Pond peat (in mesh bag).
6. Layer 4: Lava rock (top).
7. Outlet: Return to pond via waterfall/stream.

Key Tips

• Size for 1x pond volume/hour turnover.
• Seed with beneficial bacteria.
• Add floating plants (hyacinth) for shade/nutrients.
• Clean gently in pond water only.

Upflow design = efficient, low maintenance.