I've tried it all with no results

2/3 plants that I have are showing signs of issues. I'm growing outdoors in Northern California, and I'm in the 5th week of flower. The leaves on the 2 plants are clawing down like eagle claws. The leaves are also degrading. Some have bronze spots. Some are curling upwards at the tips, and some just wither up overnight and die. I have let the soil dry out completely because I did have a fungus gnat problem. I put some predatory nematodes in the soil and that did seem to put a hault to the leaf damage and curling for a couple of days. Now it's back in full force. I'm having so many leaves die, and wither up over night again.
The 2 plants that are acting up have very small buds compared the healthy one.
I'm feeding them botanicare bloom 2-2-3
Botanicare hydroplex 0-10-6
And botanicare sweet raw for sugar.
I'm using soil and my ph is 6.0 for the runoff. I don't check it going in. The ppm of the nutrient water is usually 800-1200 depending on what I decide to feed it that day. So all my numbers are normal.

I'm thinking I burnt the shit out of them with the botanicare. I have been following the directions on the bottle and I read that the directions will burn them. Any tips on flushing these out? How long should I not use nutrients? Am I on the right track?

I'm in here talking to myself. Lol. Thanks RIU.

Looks like root issues. Nothing you can really do while its in flower.
Last time I had a plant looking like that out doors ended up having a ants nest in the pot when I harvested it and pulled the root ball.

Just feed strait water till the end.