Hey, Dick: I was thinking about you when I got around to reading the latest KoiUSA. An article on water changes vs constant trickle, with wonderfully incomprehensible Norm Meck formula, concluded that even if one assumes complete mixing of new water, a constant trickle is as efficient a means to change water as emptying/re-filling up to about 20-25% of pond capacity. Of course, if mixing is not total & immediate (and on whose pond would it be?), it will be far less efficient if overflow is located in the current carrying the fresh water, and more nearly identical if the new water stays at one end of the pond due to very poor mixing. Any way, your promotion of a constant trickle came to mind. I know you focus on the stability factor, but it turns out that it is not materially less efficient than a labor-intensive water change if your pond has excellent circulation, as I know yours does. .... You are even smarter than you knew!!
