Biofall – what is it? Does your pond have one?

backyard water feature

koi pond backyard water featureA biofall is a sort of tub. It is the beginning of the waterfall.


koi pond backyard water featureThe water comes from the pump in the skimmer (if the pond has a skimmer) and goes through a pipe up to the biofall.  


koi pond backyard water featureNotice that the pipe enters at the bottom of the biofall so that the water goes through the filter pads before it can get to the top and overflow into the waterfall or stream. 

Biofalls provide filtration!

koi pond backyard water feature
In this cross-section picture you can see the place where the pipe would come in at the bottom. The water would then go through the 2 filter pads as it fills up, passing through the bioballs before coming out the spillway.

koi pond backyard water feature
The biofalls are hidden at the top where the water begins!

Hiding the biofall

The top tray of the biofall is made to help hide it.  Rocks are often used to hide the black plastic.  This is the biofall on my pond in the summer.  I had a piece of driftwood on it and added water lettuce and some sweet potato vine that was planted in the dirt just outside the biofall.  The sweet potato vine quickly grew over it and grew roots right into the water and created a beautiful green blanket. 

koi pond backyard water feature

Pro Tips :

koi pond backyard water feature Beneficial bacteria needs to be mostly undisturbed in the biofalls to do its job.  As it breaks down waste it will get sludgy.  They should be removed and cleaned out about once a year.  A good time for this to be done is at the cleanout.  (Yes, we do this when we do a cleanout!)

koi pond backyard water feature

Cleaning filters in the biofall too often actually hinders them from doing their job!


koi pond backyard water featureWater hyacinth and other plants are a fabulous way to hide biofalls and you’ve got to keep an eye on them!  My water hyacinth grew so much they diverted water out of my system.  Keep plants from overflowing the biofalls. 


koi pond backyard water featureAdd beneficial bacteria once a week to the pond in the spring and summer months.  You can add some directly to the biofall, but you don’t have to.    


koi pond backyard water feature In the winter many people do not add bacteria at all.  If this is working for you I say, do what works!  If your pond could use a little more help, add cold water bacteria in the winter.