runoff PPM elevated, how does this approach sound...

promix with some added perlite -- essentially soilless after first 5-7 days. Nearly identical to what i use, too. Runoff will be different from what the substrate is. If you weren't religiously gettign 10% runoff before, you definitely had some buildup. If the plants aren't showing any major issues, just get some extra runoff well beyond 10% the next couple fertigations and it'll bring it down to a proper equilibrium. Your plants are a bit lush, so maybe a water-only with 10% runoff for a couple irrigations is in order. i'd do it slowly vs a 'flush' just so you don't go too far the other way. If the plant was in more dire condition, a flush would be warranted. If you see the plant start to progress a bit lighter, go to a normal fertigation with 10% or more runoff shortly after that. The advantage of soiless growing and 10% runoff is not that the resulting nutrient charge is exactly what you fee, but rather that it simply remains consistent. you'll chase your own tail trying to get runoff to be exactly what you feed. that is not necessary. Consistency is what allows for formula adjustments to take effect in a predictable way. Get some symptoms? adjust formula and it'll almost immediately change the reslting ratio and concentration of nutes in the substrate... maybe 80-90% transition the first 10% runoff and ~100% by 2nd. Initial runoff will read higher than what is actually in the substrate. I never bought a TDS probe. Don't need one. Read plant, adjust formula and stick to 10% runoff or more religiously. The plant dictates how much N/P/K/Ca/Mg/S it needs. Fine tuning of the formula is 100% from observing the plant and adjusting to what it says. When your formula works for 99% of genotypes, it's a good formula. The idea that these plants are picky stems from esoteric, imbalanced fertilizer formulas... some plants may handle it, but more than a few will not. Don't blame the plant. blame the formula. probably need 70-80% of N in flower compared to vege phase but otherwise fairly consistent levels of other nutrients have great results.