Problems 48 hours after flush

[1970s Grower]

This is bagseed in a cabinet grow on Day 25 of 12/12. I am using Fox Farm Soil with Fox Farm Nutes per schedule pluse some CalMagPlus, Bud Candy, and Nirvana.

48 hours ago I did my first flush and have problems. The top most leaves are getting rust and drying out. THe bottom leaves/growth is limey. Pistils are turning brown overnight.

I flushed with:
tsp per gallon Fox Farm Sledgehammer at 2 tsp per gallon I used 2 gallons per plant to flush. The plants are in 3 gallon containers. I use RO water with the sledgehammer PH'd to 6.4 - 6.6

on the second gallon per plant I added 2 tsp of Fox Farm Big BLoom In addition to the Sledghammer. This was also PH'd properly.

These plants were perfect with no sign of disease or pests ever. Now they look like they might die, especially the top most leaves which seam to exhibit the worst symtoms. See pics below....

What could have happened?The topmost leaves are drying up and are brittle. They looked fine yesterday.

This is my first grow in almost 40 years also my first flush ever. Is there anything I do?

 

[gromper]

Flushing should be done with water only (or with some sledgehammer) and then 2x-3x the amount of water as the soil content of your pot (3 gal pot - 6-9 gallons of water. Then give it a day before adding any nutes. Flush at 4 weeks, 8 weeks and 12 weeks (if they go that long - mine rarely do).