frequency and size of water changes in planted tanks
I'm an aquarium veteran but new to planted tanks. My question is regarding the frequency of water changes in planted tanks.
For the last few years, I've been doing saltwater tanks. For years the general belief was that large, frequent water changes of 25% were necessary. Recently, with reef tanks growing in popularity, there have been tanks that have much less need for large water changes (reef tanks usually have a much lower bioload, and the deep sands many use lead to very low levels of nitrates, so it's very easy to get away with changing 5% a week). However, many reef hobbyists still perform large water changes and swear up and down that those who don't will have lots of problems, contrary to actual results. I think it's just force of habit.
Because of this, I'm wondering about water changes in planted tanks. In my normal freshwater tanks, the main concern was to dilute nutrients such as nitrates, primarily for algae control. However, I'm wondering why a planted tank would need water changes as frequently or as large as a non-planted tank. I would think that most of the nutrients would be sucked up by the plants and therefor not in the water column. What exactly is it that needs to be removed in planted tanks? If there isn't much that needs to be removed, are large water changes just a stubborn old mindset that refuses to die? One of the LFS around here has a couple of planted tanks, and they say they rarely change water compared to the non-planted tanks. Their tanks look VERY good.
Any help on clarifying this would be great. As I said, I'm new to planted tanks so I don't want my reefing prejudices to get me in trouble.