Our pond is 6,000 gallons. I change approx. 10% every day -- most of it by dumping and flushing the vortex settlement tank and backwashing/rinsing the (2) Ultima 6K mechanical filters.
Then I throw a double dose of ST crystals into the pond, turn on the hose (which pumps at 10 gallons/minute, or 600 gallons per hour), set the timer-on-a-string around my neck for an hour and get back on the 'puter.
Life is good.
