Botanic Garden >> Gardening > >> Question and Answer >> Pond and Water Gardening

White Foam in New Cement Waterfall: Defoamer or Patience?

Cause

Fresh mortar/cement releases surfactants and fine particles that foam at the waterfall. This is temporary (weeks to months) as the cement cures and leaches.

Options

Wait it out: Foam harms nothing; it's unsightly only.
Defoamer: Pond-safe silicone defoamers (e.g., Drs. Foster & Smith) break surface tension instantly.
Carbon: Activated carbon in filter helps clear organics.

Before Adding Koi

Ensure pH is stable 7.5–8.2, ammonia/nitrite zero. Run the waterfall 24/7 for 2 weeks minimum.

Pond and Water Gardening: Pond Liner vs. Concrete: Which to Choose?; Clearing Green Water in a Fishless Pond; Fixing a Murky Concrete Pond Without Fish; Restoring a Neglected Backyard Pond for Safe Swimming; pH Adjustment for Fish Transfer: Raise Old Pond, Not Lower New; Overwintering Pond Goldfish: When to Bring Them Inside; Foam & Algae After Pond Liner Repair; Foam and Algae in Concrete Pond: Protein Skimmer Solution?; Pond Bubbles and Foam: DOC, Soap, or Gas?; Foam, White Algae, and Lethargic Fish After Filter Cleaning

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