1 week old seedling in soil has runoff ppm of 2500. should i flush?

Did you have them in a humidity dome at all? Moving from a dome to fresh air can cause this effect on starter leaves. 🤘😤

Weird leaves at the start is not a big deal. Feel the leaf with your fingers. Is it papery or moist. This might tell you if you need more or less water. From my understanding Fox Farm runs hot. I would not waist nutrients by flushing. Your plant will adapt. Keep a close eye on them and make sure the following: 1. Light is not to close / hot seedlings need time to adjust to their environment. Light shoudl start at 36 inches away until the plant is comfortable. You could make it easier on them by raising light and reducing heat if either of those are a problem. 2. Humidity in Room is between 50-60% anything above or below will cause problems. 3. Getting appropriate amounts of water. 4.Whether or not your water has enough dissolved minerals in it. Usually in the first 3 weeks if your water is light on minerals you will get yellowing. This can be solved with 1/4 tsp of Epson Salt in 1 Litre of water. 5. I had trouble with my plants at the start (different problem) also using Fox Farm. My plants grew very slow. I added 4 drops of General Hydroponics Rapid Start Root Enhancer. (This is the ONLY "Liquid nutrient" I have used) the rest is all Compost Tea and Dry Amendments but it really helped bring my plants to life at the start. Think I used 4 drops in 1 Litre of water. Hope this helps!

The look quite casual to me. You may be experiencing a bit of overwatering tho. Stay lit growmie.

They look just fine to me, if not a bit thirsty. Some plants just have strange leaves. I think you may run into trouble flushing such small plants. They are still tender babies at this age.