Placing the jets at the bottom of your koi pond will help move sunken debris to your bottom drain.
Consider this. Hydrostatic pressure increases the deeper you go into your pond. Because of this, a jet or TPR (to pond return) becomes less effective the deeper you place it. Placing your jets on the bottom of your koi pond decreases their overall effective range, providing little help for cleaning the bottom of your pond.
When used properly, jets are a necessary addition to any koi pond. When placed about twelve inches below the surface, jets have an effective range of about seven feet when 5 GPM of water is being sent through them. Jets should be used in tandem with any waterfalls and skimmers placed in the pond to create a self-cleaning surface.
Place your jets twelve inches below water level, pointing them slightly toward the surface and to the skimmer. This will help create a gentle current on the top of your koi pond that directs leaves and dissolved organic compounds (DOC) to your skimmer.
8’x10’ rectangle pond – 4 jets circulating the water towards the skimmer