Are you not dosing a separate potassium source(k2s04) since your Nitrate and Phosphates already have some in each? Have you had luck with this in the past?
Your having amazing results, sorry about the cardinals btw. I just started a similar setup last week but now am kicking myself for not ever even hearing about tissue cultured plants. I am experiencing a lot of melting with my HC, half of each portion planted so far. They are adjusting to being submerged I guess.
Also, I battled with BBA for a long time, it actually caused me to give up a few years back. Ended up just having a 120g driftwood biotope for my discus instead. Now I'm back and trying plants on a smaller scale separate 20g tank.
Anyway, thanks for such a detailed journal, it's helping me already!