I'm not really sure- Rex is on some high horse about tech specs(I think it's mainly because he wants to argue with people about things he's never tried) Anyway, he says it's not LEGALLY a fertilizer because it 's not x% this and y% that. I say it IS a very comprehensive fertilizer if you consider a fertilizer a mix of supplents that makes you plants grow like crazy. He seems to know more about what's in YG than the people who make it (who will happily talk to you about it if you call them- the guy spent a half hour on the phone with me the first time I bought it, and not "salesing" me up)-it's very funny.
The the difference i have seen with YG vs Flourish (which is what I used to use, as well as an Aquarium pharmacudical product i don't remeber the name of and a couple other liquid ferts) is that you only need one thing. They include it all, without making it so you have to buy2-5 bottles.(unless you need something that is probably already in your tank like Nitrogen which you can get Yamato-N for) Plus, it works a lot better. Rex reffers to me as a "yamato green pimp" (and it was soley me who he was talking about) but the difference between him and I is that I haven't tried dry ferts yet-and I'm open to it. He's never tried YG and has something against it.
hey- everyone's different. I say YG is woth a 6 week trial at least. Worst thing that happens is you end up wasting less than $20. In my opinion- ANY amount of money is wasted on something that doesn't work, or doesn't work well, and money spent one something that gives you a jungle is well spent!
Oh- One last thing - the key to why the stuff works so well (according to the makers) It contains growth stimulators. they won't say exactly which, or how much or anything, but they are present, and they're the key as to how you can mix the same "formula" at home that's on the bottle and not get the same results. Can you tell I LOVE the stuff?