What the hell is going on?

Hi guys
I can't figure what's going on with this plant!
It looks like burn so I flushed it and it's still getting worse. I've since fed it at quarter strength but it's getting worse.
Can someone give me advise on what to do?? I'm lost here and she's got at least 3 weeks to go
Thanks !

How much did you flush with? It looks like calcium and magnesium deficiency to me. Magnesium would cause the yellowing and calcium the browning. This could easily stem from a small pH issue, because Cal and Mag both become unavailable at a certain level of acidity. Try bumping up your pH a bit.

Ok thanks - so I've just given her a little Epsom salts - that will help the mag. What can I use for cal?

Also - I've been using HG nutes - a&b soil.. I thought everything I needed was in these no??

calmag def. .usually is spotty rust color.. its prob lock out do to ph... whats the ph?