Recipe needed..c'mon you soil chefs help a guy out....

Not a big issue but I have a slight ph problem and need to lower it. I will be using vinegar to accomplish this. What I need to know is about how much vinegar would I need to add to a gallon of water to lower 3 gallons of soil 2 full ph points?? I never really had this issue before I also intend to lower my nute dosage. Thanks!

I use FFHF, always have. I am using the trios for the first time though both liquid and soluable. I know I slightly overdosed causing the issue. I have used other nutes in the past but I am trying an all fox farm system for the first time. I am not going to spend $15 or more for ph down when vinegar works.