Actually it seems there are good and bad aspects of each;
a LARGE single water change, though it removes bad water contaminants and adds trace elements BETTER, also may shock your inhabitants MORE
a SMALL water change is less beneficial with diluting out toxins/nitrates/etc. and adding trace elements, but is MUCH LESS OF A STRESS EVENT than larger...
I do about 10 percent a week. I've heard that it's overkill. All I can say in response is that my corals and fish are extremely healthy. A book I've read (can't remember the name) suggests that regular water changes are important and that everyone had a differing opinion. He stated that someone with a 200+ gallon tank does gallon water changes daily (which seems really odd). Point being it's most important to have a good routine. I think everyone's system is different, and you will know how yours reacts better than others. I would say if you are in a habit of doing your 3-4 gallon water changes weekly and you are checking your water quality regularly that you are doing the right thing. I'm only a newbie reefkeeper and some more experienced guys might tell you different. Either way, best of luck.
If it works for you ignore everyone else..the fact that you are already practicing this speaks for itself..if the tank hasn't had a chance to build up a lot of toxins then this practice should keep it from doing so..while minimizing the animal stress..reef stress brings a whole new meaning to "stress kills" if it were me I would always take the least stress route...
Even if you change 3 to 4 gallons every couple of days I feel like you are causing less stress than you would with a major wc..
The only time I would do a major W/C would be if there is more stress from really poor water quality due to somthing dying in the tank or some other harmful water quality.
