This is a very common question I receive every spring.
A clean, clear pond full of healthy, happy koi fish should not be power washed every year!
“Mother Nature” works very hard and long to create the fragile “biological balance” of your koi pond. It does not take much to destroy this natural balance. However, it could take many months for your koi pond to recover to a healthy natural balance after a thorough cleaning. In the meantime your koi fish are being stressed.
My suggestion for spring koi pond cleaning is to remove the sludge, leaves, and twigs on the bottom of your pond. Don’t touch the green algae on your rocks and the sides of your pond. Remove all sludge from your pond filter.
Never wash your pond filter or filter pads with your tap water if you have “City Water” which contains chlorine, it will kill your “good bacteria” in your pond filter.
Weekly pond water changes are priceless to health of your koi fish and pond. Just “topping off” your koi pond water due to evaporation is not considered a water change.
It’s very unnatural for koi fish ponds to have sparkling clean rocks and sides free of healthy green algae.
If you want your pond to be sparkling clean and algae free, I suggest you have a fish-less pond.
Then you can add all the toxic algaecides you want. Plus, you can have it power washed as often as you want.
Question: Are there times when a good power wash clean out is necessary for a koi pond?
Answer: Yes, when sludge and debris become so deep it’s impossible to remove it all with the pond full of fish and water.
Some koi ponds become “sick” because of poor maintenance, lack of weekly pond water changes and they have to be power washed and cleaned.