What Roberta says ^^ Kelpmax isn't a fertilizer. I wouldn't think using it as diluted as Shadeflower is doing is harmful. Likely not necessary, but if it works for him why not?
I "try" to use Kelpmax once a month. Sometimes it doesn't happen. For what it's worth, I use one Tablespoon per gallon, because that's how we measure stuff here in my neck of the woods. Have no idea whether that's equivalent to what Camille said about milliliter to liter, and would hate to try converting and screw it up. So if of interest, please do your own math...it makes my head hurt too much.