I don't think you'll see any issues with K as long as you dose K2SO4
once a week(say 1/4 teaspoon once a week per 20 gallons) etc and if
you use KNO3, you get a fair amount of K from that, which is also
dosed 2-3x a week typically.
It's darn near impossible run low on that if you do the above
routines.
K is hard to test for with the test kits available in the upper
ranges.

Regards,
Tom Barr