Green Bubbles on 1,500-Gal Pond: Overstocked, Add Filtration & Plants

1,500-gal pond, 1 koi + 99 large goldfish (½ lb each), UV + filter, green bubbles, Green Away failed. Massively overstocked.

Stocking Math

• 99 goldfish × 12" = 1,188" fish.
• Rule: 30–50 gal/inch → need 35,000–60,000 gal.
• You have 1,500 gal = 25–40× overstocked.

Fixes

1. Reduce fish drastically — rehome 90%.
2. Filter: 2,000+ GPH minimum — add second filter (author uses 2,600 + 700).
3. Plants: 60% cover — lilies, marginals, submerged.
4. Bacteria + barley straw — weekly.
5. Feed less — reduces waste.

UV Limitation

UV kills suspended algae only — not surface bubbles (hair/blue-green algae). Manual removal + filtration needed.

Your pond is a fish factory, not a pond. Thin the herd. Build the filtration. Plant the surface.