Filtration & Muck in 400-Gal Pond: Lily Pots & Solutions

400-gal pond (expanding to 500), 1200 GPH pump, Tetra biofilter, waterfall to 20-gal upper pond. 3 koi (9–11"), 10 goldfish, mosquito fish, 5 lilies, 15 hyacinths. ¼" brown muck covers bottom/sides, clouds when disturbed. Asks about bottom drain/skimmer.

Muck Source: Lily Pots

Soil escaping from lily pots is the likely culprit. Hyacinths in rock corral may also contribute.

Fixes

1. Top all pots with 1–2" pea gravel.
2. Repot lilies in clay loam, not light aquatic soil.
3. Add fine filter pad in biofilter (clean weekly).
4. Coagulant (AccuClear) for existing muck.
5. Siphon/vacuum bottom during water changes.

Skimmer/Bottom Drain?

Not needed at this size. Fix pot soil loss first. 350 GPH spare pump → small fountain for extra aeration.

Overstocked: 3 koi + 10 goldfish in 400 gal = high load. Plan expansion to 500+ gal soon.