Hey Growmie, I also use advanced nutrients, but am using soil. When I mix my solution, and there’s some left over in the pail, that’s what I see after a day or two of it sitting. Little brown floaters that look like fish food… obviously not a solution that can be kept for very long. I don’t think it’s specific to you, adjust how long your solution is kept in reserve and see if it changes. Good luck Growmie ❤️🇨🇦👊