Rubbish. Complete junk.
I am being serious.
I think running carbon 24/7/365 can do some harm but the good it does outweighs the bad by A LOT!
What the author didn't mention was that carbon removes the toxins that corals release. In such a small environment like we have, we can't have corals waging war or one will win and the others die. Potentially wiping out a tank and all of its inhabitants.
Is that something you want to risk?
Dosing trace elements is a great way to replace whatever carbon pulls out, if any. I have run carbon on all of my tanks over the last 4 years. I run mine 24/7 and have NEVER seen one negative effect from Carbon. I have actually seen positive results using it.