When I had my 100 gallon setup, I could go 3 months without a water change. My Nitrates never got above 5. But, I had to supplement Ca. and Magnesium.
~Michael
Now I do 10 gallon water changes every other week in my 55 gallon. Not due to High Nitrates, just to keep my Ca. and Magnesium levels in check.
~Michael
I wouldn't take that approach espeically with a 29g tank. There are a lot more things that need to be replaced and unless you have a whole arsenal of tests at your disposal you're dosing blindly. It really depends on the tank itself but the more life in the tank (corals, fish, inverts) the more critical water changes are. With a stable tank you can do much smaller water changes (Like Frankie) but still do them. Put this into HUMAN terms. Would you want to live in a jar that's closed up tight (air tight) with just a bunch of fans moving the air around for months on end? Wouldn't it be nice to once a week get to open the window and let some of the "polluted" air out and some fresh air in? The larger more mature/stable a system is the longer you can "Stretch" the water change but if you're wanting to really PUSH it do smaller water changes for the health of everyone in the tank. Remember the water change is almost VERY important for exporting other things than JUST Nitrates. It just happens on most systems that's the ONLY way to export them.
I see your point. Yes for some corals our tanks are indeed "too clean" but we also have to factor in that many of our corals need BETTER conditions than what we give them. We're trying to fit a whole ocean of different animals into a very closed loop system.
If what you're doing is working then keep doing that. What works for one tank may or may not work for many others. That's part of the beauty of this hobby.. we learn all we can and then "apply" that knowledge and then we tweak it for what works for us.
Only thing I want to point out is that the majority of your established bacteria is NOT in the water column under normal circumstances and water changes shouldn't negatively affect your biological filtration unless you're stirring up the sand or disturbing the live rock itself. If you're "turkey basting" and "raking sand" then yes you're suspending SOME of the bacteria in the water column but that's the exception not the rule.
Keep up the good work