I haven't boosted potassium... But a friend did suggest Bloombastic
Root rot will always cost you
find a nice stable feed you like, go 500pp to 1000ppm (strain depending) after week 4 start adding 200ppm to 800ppm of potassium sulphate
obviously use whatever products suit you to stop the rot next time, go bennies or sterile up to you, but potassium sulphate is the main thing I`d add once I`d found a good all round bloom feed
after that you can try spraying or feeding triacontanol but get your hydro rot free then start adding some K 1st
I feed just sugar or potassium sulphate for 1 to 4 weeks before cutting, some people find normal feeding or just water works better, I like my way.