Do I really need to buy?

[reefwars]

Sorry my bad what I should have said is unless done in large amounts water changes are a poor nutrient export

[gobytron]

Can you forward me the articles where that is stated please?

If you read that article from wet web media, or the conscientious marine aquarist, which was written by Robert Fenner (who I can't help but trust) you will read that more frequent smaller water changes are actually preferable to larger water changes less often.

Very possible there has been some new research on this, maybe that is what you are referring to?

Can you please post some links to the articles you mentioned that state this as fact?

I would be very interested to read them.