MG is fine bro. I used to be confused by all the negative information online about MG. Until I researched their fertilizer metal contents on several independent testing sites. MG has no more heavy metal content than Jacks or Schulz or any other salt makers.
SALTS IS SALTS they just come in different ratios and prices. I've grown a few test plants using 18-18-21 in flower.. and a cross of 24-8-16 and 18-18-21 in veg....and they came out fine. No black ash burning it, no headaches. Totally normal, unlike what some people try to convince you online. Salts are salts