The yellowing " from the edge in" followed by the sudden mortality is making me wonder (strongly) about a calcium def.

You pretty much always want to use Calmag w/ PBP, unless your water is signifigantly Ca hard.

Drop the superthrive, too- it'll delay finish.

I would have a look at one of the troubleshooting guides- don't have links handy, but googling " jackerspackle" will get you to the old OG version.

I don't think that your problem is N.
rhizome Reviewed by rhizome on . Nitrogen Mayday! My nitrogen deficient plants are getting worse! I don't know what to do! Pretty much all the large fan leaves of the one plant have been consumed, and now my best looking plant is starting to turn really yellow towards the top. I am on day 23 today. What the F should I do? Rating: 5