In terms of the "macronutrients", kelp and lavar is quite comparable. Lavar is lower in calcium and magnesium, but is richer in potassium. This is as far as I got scientifically and I pretty much made up my recipe for the fertilizer. I took 2 sheets of nori and shredded it before adding to a gallon of water. I also added 3 tablespoon of coffee (for nitrogen) and 3 tablespoon of crushed eggshells (for calcium).