I agree with what others said. General Hydroponics uses high quality salts-their products like FloraNova and Maxibloom/Grow, all regularly test below detectable limits for heavy metals, and I think the Duo does too, all of them use the same base salts. You will have success with their 1, 2, or 3 part nutrients, but as Xtsho said, in the future, dry salts are the way to go. Since Maxibloom is using the same salts, you are just paying extra for the water and it's weight. I'm actually using up the last of my Maxibloom (complete, single part dry salt formula) and I'm switching over to Megacrop A/B (Jack's A/B is nearly identical, both are good options). If you already have the Duo nutes, by all means use them up! Some of my best grows have been using Gen Hydro nutes, including my current one, but when you are ready to save some cash AND grow amazing bud, check out the 2 part nutrients I mentioned.