@Greggz point was that it doesnt do anything to help plants grow. He did agree that its an algaecide, but that only helps plants indirectly.
The growth process affected by glut, as you know, is splattered everywhere on this forum and the web, so I don’t want to get into that, here. I think that everything I’m about to say is well known to you, so this is mainly for others that may not be aware.
Significant? Can you quantify that?The carbon contribution of Excel-like products is insignificant as compared to CO2 injection, but it is significant as compared to atmospheric contribution of carbon
My personal belief and having used Excel in low-tech is that it can help increase growth, but not by providing carbon. I think it simply "cleanses" things and makes it easier for some plants to uptake nutrients on the leaf surface. We all know it's not co2 and it hasn't been shown anywhere that the plant is up-taking a useful form of carbon. I honestly think in many cases, just better maintenance/light mgmt will do the same thing....The carbon contribution of Excel-like products is insignificant as compared to CO2 injection, but it is significant as compared to atmospheric contribution of carbon, and that is where it is useful as a growth-promoting supplement. It would be wasteful to use it in a high-tech tank to promote growth, unless using it purely as an algaecide...
C'mon, now: nobody can quantify much of anything in this hobby, e.g.; can you quantify what is insignificant about it?Significant? Can you quantify that?
As to damaging plants, too much Excel can weaken any plant. The issue is people overdose hoping to help the tank and exactly the opposite can happen. I've even seen people dip plants directly into Excel and are surprised when they melt. It kills things. That's what it is designed for.
But like you said, this has been debated many times over, and neither one of us are likely to change many minds. I don't believe it has any real benefit, while others do. .