Q: I top off my pond for evaporation, so why do I need to do water changes?
Joan – Bethesda, MD
A: Topping off your pond with fresh water isn’t quite the same thing as a water change. Think of it like the oil in your car: You may “top it off” when the lubricant gets low, but to keep your motor humming, you need to do a complete oil change every 3,000 miles or so to remove the dirty oil that’s full of sludge and combustion by-products.
It’s the same idea with the water in your pond.
Adding water every week or so to replenish any lost from evaporation is certainly important—but it does nothing to remove the sludge, or algae-feeding nutrients, in your pond. As the water evaporates, the gunk stays behind and concentrates. Your filter does a good job removing the pollutants, but unfortunately it’s not always enough.
So why do water changes?
- Remove the buildup of nutrients, like nitrates and phosphates
- Promote fish health, as their well-being is directly related to your water quality
- Reduce algae blooms
To keep buildup under control, we recommend you change 10 percent of your water every week, or 20 percent of your water every two weeks. Many pond owners use a spare pump and hose to draw out the dirty water and send it down the drain. If you have a pressure filter, using its back flush feature is the perfect way to make the water change.
If your tap water has chlorine or other heavy metals, don’t forget to make it safe with Pond Logic® Water Conditioner. It removes chlorine, destroys chloramines and detoxifies heavy metals. One ounce treats 500 gallons.
In addition, make sure you add some beneficial bacteria to the mix, like Pond Logic® Nature’s Defense® or LiquidClear™, because when you change the water, some good stuff goes out with the bad! Both products contain microorganisms that instantly activate once they hit the water, multiplying every 20 to 40 minutes as they digest organics in your pond.
Make water changes a regular part of your pond-maintenance routine.
Pond Talk: What water-change routine has worked well in your water garden or koi pond?