@farside05 I've certainly noticed in journals/ other contemporaneous writings that, in the last two years, all the single ratio Jacks etc growers bumped up their K numbers 10-15 percent. My slurry still tests ec 1.1-2, down from 1.3, but don't feel like I can strengthen my ppms in rez.
Really, my animating concern with this grow/ and salts in SIPs has been retention and then throwing a blockage as result. I figured some strong castings and a weak rez might get me through w/o flushing. However, if a single preventative flush were thought to be all I needed to get through, then that I would do readily.
I suppose flushing water through the mix from the top would be most effective... What if I were to block the overflow instead and fill rez with clean water, permitting water level in rez to rise into the bottom 6 inches of soil, where all the nute is anyway? I can have an air pump going to make sure I don't drown plants.
This fear of retention triggered lockout is really why I have low strength salts nute rez. and organic amendments in sunshine mix.
@Buds Buddy made the switch to sips a grow ago and had good results. He's switching over even more of his grow op now. He may be able to address your concerns better. I doubt I'll ever go that route or full hydro. For my space and setup I need my plants to be easily mobile. For the same reason I'll likely never use a scrog net either.
PS, crunched some numbers. 278.2g of Muriate of Potash (Potassium Chloride) combined with a gallon of Distilled water makes a solution that is 10 ppm of K for every ml dosed.