I can agree that the prices of these products at least on amazon are not fairly priced. But it's the difference between a 300$ ballast and a 60$ ballast or a 990$ Valoya and a 180$ Viparspectra.
These Pioneers take their job seriously and investigate, research and develop wonderful products and after spending Time and MONEY to figure out what works best they release it to make their money back only to have assholes reverse engineer it and sell it mass production style and undercut the market. With these fertilizer salts in particular, hydroponic marketing does take its toll.
It's the same as the age old debate of Chinese made and "Product of USA"
If no one bought the Pioneers product and only went to buy the cheaper market undercut than we would lose out on the R&D department of wonderful businesses and the advances in the industry would halt. If this continues, we will have discouraged any growth in our favorite market and stay complacent.
Guaranteed analysis, customer support and above all research and development are what the "extra cost" goes to.
Go to Miracle gro's website and try to find a guaranteed analysis. They change from state to state. Using urea (anhydrous ammonia (NH3) and potassium nitrate) as a main source of nitrogen is a joke. Ammonium Sulfate is both sustainable and more effective at Nitrogen delivery. Phosphoric acid? Your joking right? You mean hydroponic Ph down? Not a source of phosphorus for plants. Phosphorus gets locked up in soil the easiest, meaning it creates a bond with soil particles and becomes unavailable for plants and you want to use solid phosphorus as a fertilizer?? Just No.
Mono-ammonium Phosphate (MAP) the bond between ammonium and phosphate is strong enough to stay water soluble. Next you're going to say rock phosphate (Only soluble with Ph <5.5 and non sustainable) or even calcium phosphate (95% water insoluble IT'S OUR BONES) can be a fertilizer because you saw the word phosphorus in it.
Support research and development, it's the real reason THC came up from <10% to an astonishing 35% not a few decades of breeding. It's (Cannabis) been around longer than our collective sources of information, if THC is used as a self defense mechanism it would have raised the content all on it's own just like it figured out how to make it and use it, it could have figured out how to synthesize it even in low nutrient profiles. Just like microbe synergy.
If you can't afford 10$ for 200 Gallons, I sincerely believe you are either in the wrong hobby, or are very wasteful as I can get away with using <50 gallons per plant on a 4 week veg and 8 week Flower. 36 is something I strived for in an economical grow. (Flushing is a leisure not available to those with a water tank as a source, as well as "Runoff" why flush excess salts instead of using them, Why even get to the point of an excess?)
N+P+K+Kelp+CaMg= 50$ for 200 Gallons. why is this an even an issue when 1 Liter of Advanced nutrients (Yes, it's used commercially too) at 4ml/L makes 64 Gallons and Costs 35 for the GMB and 120$ for con/sensi Grow A+B and Bloom A+B??
Conclusion:
Use what works for you but understand how it could hurt you if someone was buying the "same" product from someone else at half the cost. I mean, you cared for and spent time and resources to create something your proud of and just because someone caught a seed in your bud and grew it with miracle gro, they could undercut you.
Roll It Up my friends.
