NPK serving

it's 1% of the mass, which will vary by product unless they are the same mass in total. you can apply algebra based on mass differences of the products you have and weight the label % and add them up. or, you can download my nutrient spreadsheet from my profile comments and enter label information for upto 10 products, and it'll calculate ppm for you -- which is a value you can compare to others and make some educated guesstimates about what to do when a problem shows up or simply avoid them for the most part after a little trial and error. There are also numerous nute calculators on the web. so, you'd enter your liquid kelp info with 3 'servings' converted to how the spreadsheet works (g/gal or mL/gal) and it'll tell you ppm of N. it can handle ingerdients listed as %w/w, dry or whatever. limited conversion of inputs as of yet. i'll update that later when i feel motivated. that's another thing i'll fix.. it started as g/gal because that's what i use, and i added functionality over time. that'll be more generic and uniform at some point.