What are you guys doing for liquid fertilizer rates directly in the trench for soybeans?

Im a first generation farmer with an old 7100 jd planter with liquid fertilizer going directly in the trench it’s not set up with 2by2 or anything like that.. I ran 3 gallons of 3-18-18 and 5 gallons of water this last spring for a total of 8gallons per acre so I had a steady flow throughout the trench. Now my question, is 3 gallons of product to much for the seed? Is 5 gallons of water just ruining and diluting the product? Thanks everyone!