What's the White Foam in my Pond?
Drs. Foster & Smith Educational Staff

How to prevent foam under water features.

If your water feature has a waterfall or fountain, you're probably used to some foam or froth from normal water agitation. But if that foam keeps accumulating and doesn't dissipate, spreading like a white carpet across your pond, it may be a sign of an underlying problem with your water conditions.

Typical Waterfall
Foamy Waterfall

Stubborn bubbles are commonly due to an excess of dissolved organics and/or proteins collecting in a slick along the water's surface, creating the same effect as suds in your bubble bath. If you're scratching your head over pond foam, consider these possibilities and recommended solutions:

Is your pond out of balance?
Use a Test Kit to check for ammonia, nitrite, and nitrate. Trace amounts of nitrate are acceptable, but if any ammonia or nitrite are present, your pond may not be cycled correctly and you'll need to add more filtration or additives to bring conditions back into balance.

Are you keeping too many fish?
High nitrate can mean that you have more fish in your pond than your filter can handle. Short of reducing your fish population, you can pack your filter with activated carbon to lower the amount of organics your filter must process.

Is your filter too small?
If your filter isn't adequately sized for your pond's volume, residual organics from fish waste and plant decay may be collecting on the water surface. One solution is to get a larger filter; remember, it's always safer to use a larger filter than recommended by the manufacturer.


Have you recently used a dechlorinator?
The same solutions you may use during water changes to make your tap water safe for koi can also cause foam buildup. If this is bothersome, try a water purifier system especially made for ponds instead, like the PondFil Float, which connects to your outdoor faucet/garden hose and automatically adds filtered water back into your pond when it drops below a certain level - from evaporation or normal water changes. In addition to getting to the root of the problem, there are some "quick fix" products which target nuisance foam directly. Try a defoaming agent to keep the surface of your pond a clear reflection of all your hard work and creativity.

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