I flushed with fox farm sledgehammer to remove exc...

Hi @GrowFanatic! Well, since you used a product to get rid of salts/nutrients/chemicals, your plant is trying to find energy elsewhere, so basically it's eating the few nutrients left in the leaves. That's a normal thing, leaves are supposed to fade when harvest is coming / when the flush has started. This phenomenon is called "senescence" and is part of the pre-harvest process. No worries, this reaction is completely normal. However, I think you still have a few weeks to go through before harvest, so I'd recommend to give them at least 2-3 last meals, before flushing for 7-14 days depending on the trichome's evolution. Hope this will help, keep us up-to-date and happy growing 👊