I feed them kusuri pellets once a day and they seem to eat it aOUTll after ten minutes unless it’s sunk and I can’t see it.
That's probably problem number one, it takes my fish less than 10 seconds to wipe out the food on the surface. I MAY GIVE A SECOND HANDFUL, but again its gone in seconds look at every pellet as a hamburger three should be way more than enough. Small more often feedings is what the koi raised ponders go with . Boggers we do far less and encourage the koi to graze as that what they are.
What size micron mesh are you using? 300, 200, 100, 70?
i use a bog filter my water is clear to where i can see a dime amongst all the rock down 6 feet. But for a polish i am in the process of a dyi sieve im leaning toward a 100 micron
16,700 liters is only 4500 gallons and that equals to you are over crowding i'm counting 16 good sized fish? mostly koi? One large koi should have around 1000 gallons on it's own and a minmum of 500 gallons for each after that.
This can be altered by increasing how many times you turn over the pond an hour. which brings me to the next question how many liters per hour does your pump and filter run at?
along with the drum filter what else are you running a fluid bead filter? a foam block ? pressure filter?
