Each type of nutrient brand, strain, type of medium, general invioriment, all these things take a part in how much Nuts your plant can take. This is why people build up slowly to figure out how high of ppm their grow can go.

I am one to talk though, I changed strains, brand of Nutrients and even additives, to the grow I am on now. Luckily I caught the problem early. One person even said something about my plants looking like a gave them radioactive nutrients, but who cared, if they have nice buds. lol....

Even if you fix the trouble, you will not see the change in the growth that is there. The change will be in your new growth.