Composicion relativa entre fertilizantes?

the pk 13/14 is probably monopotassium phosphate? if you compare guaranteed analysis labels, you can see exactly what each is made of. a specific molecule always acts the same under same contexts. this is no "high-end" monopotassium phosphaate, therefore the cheapest brand of MKP is the best. magnesium sulfate is always magnesium sulfate etc etc... methods of irrigation are mosty the same. you may not want as much runoff with soil compared to soilless, but you still want a little to ensure the whole thing is properly saturted. many "pot' brands tell you to feed 2-3x too much. you can always use a nutrient ppm calculator to compare apples to apples between formulas. ther's no magic fertiizer.. they are made of the same group of active ingredients even if some variation of ingredients is possible. signs of a good fertilier -- not too many parts, includes everything you need, ph-blanced etc etc... and cheap. fertilizer is cheap. any fertilier priced at premium is just packing in a larger profit margin.