think they instruct some insane 2EC dose ... don't follow their instructions.
if they don't have guaranteed analysis labels... good luck figuring it out each time you buy the bottle, LOL
if it does, it is worth doing the math at least once to convert what you feed into PPM per molecule as well as in total. The ballpark idea will be good enouhg for any minor adjustments to the formula you settle on. google 'nutrient ppm calculator" manic botanix or some shit like that should be near top of list. it can handle specific gravity, if necessary.
i'd just avoid feeding for a while. you are in soil, right? whatever cycle you were on before, give an extra irrigation between feeds of just water.... if it continues to decline, maybe 2 extra water-only irrigations.
Some runoff in soil is good. you don't need as much as a soilless grower.. just make suer the whole thing gets wet... dry pockets can have all sorts of ramifications down the line.. as teh dryback continually increases concentration in those zones much more than if it was fully saturated each time. this results in some runoff being necessary. if you got fabric pots, feel at bottom.. is it wet? or if nursery pots, make sure the substrate is equally moist at muttiple drain holes at bottom.. be surprised what a little slope can cause... 1 side will need a little more water or rotate the pot half way through....