Glad to hear you have a "break through".
That said,low nutrients and "run away" bacteria is flirting with disaster...
My opinion is just that KNo3 is WAY more risky than NaN03. Potassium "crashing" is real. A little Kno3 is fine if a little bump is needed to get N03 up, but K over 400ppm in your DT quickly plays with fire....around 460 or 470 BOOM. NaN03 doesn't have any identified risk, beyond "too much too fast"...but with steady rates you can get to 20ppm before anything significantly negative happens.
On a different topic, I found struggles when P04 rose faster than N03...all sorts of algae blooms and stability issues. Hard to get N03 up without pushing P04 even higher....
If both are low, feed more and get the good bacteria type population up via DrTim's, Seachem Stability, Fitzym, etc.
If N03 is immeasurable and P04 is 0.1 or higher, dose enough NaNo3 to maintain N03 above 2ppm...and get onto a disciplined maintenance schedule to finish what you have begun.
Good luck and thanks for sharing your journey~
Not sure I've heard of low P04 with N03 above 2ppm...I'd be interested to hear if you have that! If that happened to me, I'd feed more and dose bacteria to process the nitrogen.