Wood ashes are very high in pH. Either way, you would have wound up in this situation before long. Keep any AACT drenching to a once weekly application. It can definitely be over done, especially if your adding molasses to the brew.
If you want to supplement potassium, coconut water is an excellent way to do that. Especially for small plants, it alot more gentle than potash on your pH.
The flush certainly will help I’d just be mindful of carbonate accumulation. Mabey leave a bucket outside to collect rain water, that can be your water source for in-between watering with the hose. Refrain from any fertilizing until they look like they need something. Every situation is different due to varying environmental influences but the plants will show when they need food. Id estimate waiting 1 week possibly less. Remember they have nutrients in the compost already in the mix.
You seem like a very attentive grower so I’m confident you’ll see the color lighten up before they starve and yellow out.