I'd personally give it a maintenance flush as you can afford too. Within a day or so, you'd see her perk up. You can see how she responds to that, and if still ok continue with plain pH'd water. When and if you go on the nutrients, start at half, maybe quarter strength of recommended dose. Only use the nutrients if plants begin showing deficiencies or as a little booster to encourage growth, but don't use it all the time. For every nutrient feed, give two normal plain waterings. Also, it looks to me like leaf spot fungus starting on the affected leaves.