I see 2 problems with trickle water changes.
1 - Waste of resource (water) If you're on a well, it's extra work for the well pump, if you're on a meter, extra expense.
2 - Cannot be running during the winter, so if you have been relying on a trickle water change to maintain good water quality, you may have a buildup of organic material that will continue to decompose when the trickle water change is not running. If you were focused on no water changes throughout the year, your pond may be in better balance on it's own going into winter.
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Yeah Mitch I don't see those as problems, not for me anyway.
1 - "Waste" is relative term. Is it a waste to use electricity to run a pump (or pumps) to circulate water in our ponds? After all we don't really need to have a pond and people without ponds might think we are "wasting" electricity. But as humans we tend to "waste" money on things that amuse us, make us happy or we feel are necessary or helpful. I'm no different I guess.
On top of that I pay a flat (yearly) rate for my water on a community well. I have a tiny lawn and moderately sized vegetable garden all of which are on automatic and efficient irrigation system that use very little water, but still probably use much more water than my drip water change system uses. My neighbors on the other hand use old inefficient irrigation systems which is like leaving their taps open and they run them full blast ,all day long. You could fill a small swimming pool (9500 gal) in that amount of time. My drip on the other hand is constant, but very minimal. it would take 197 days to fill that same pool by my calculations (2 gph drip), and it would take about 62 days to do a 100% water change in my pond. (3000 gal pond) Not that that would really be possible, but volume wise that would be 3000 gal out and 3000 gal in.
2 - First lets clarify that neither I nor most people are "relying" exclusively on water changes to maintain good water conditions, it is simply one of multitude of things you can do to help maintain good water quality.
With that out of the way I will say that my winter pond conditions are completely different than summer conditions.
In the winter I shut most of my pond down and only circulate the water through one of my pumps and my settlement tank, and of course the fish frogs and turtle become pretty inactive and don't eat or produce the waste like they do in the summer. Plants don't grow and water temps stay very low. Also in my case I tend to get a lot more precipitation in the winter then I do in the summer, much of it in the way of snow. Having said that early spring is probably the most critical time for water quality in my pond. The snow and ice build up on top of my pond tends to melt within a very short time increasing the PH and changing the temperature fairly rapidly, which is one reason I like to get the trickle water change happening as soon as possible, it slowly and gently adds a constant source of balance water.