DIY Pond Filter and Foam Bubbles in Holding Tank

Pond Filter Design (9×2×2 ft)

Use external filter (waterfall/stream) – easier to maintain, aerates water. Build:

1. Settlement chamber (first 2 ft) – heavy solids drop out.
2. Brush/foam mechanical stage – clean weekly.
3. Biological media (Japanese mats, Kaldness) – clean rarely.
4. Pump in pond → filter → waterfall return.
5. Add plants in filter (watercress, iris) for extra nutrient uptake.

Foam in Holding Tank (3×2×10 in, 14 koi <12″)

Foam on fill, clears in 2–3 days. Source water?

• City water: Surfactants, organics → foam. Let age 24 hrs with aeration.
• Well water: Dissolved gases, organics.
• Overfeeding: Protein foam.

Fix

Age new water in separate container with aeration 24 hrs before adding. Use protein skimmer if persistent. Reduce feeding.