<span class="link_user">@Herb420</span>, hello!
I am sure that your issue is overwatering. I am watering my plants by hand, seedlings the same. I need to use a bit of PH down to obtain the desired PH, thats means approx 6 for me. I am watering the seedlings once at 3 days but without runoff. And I always check the pot to be light, so no water left inside before watering. if its heavy, I will wait one more day. I had problems with overwatering before and now I am doing my best to avoid it :)
<span class="link_user">@Gumuservi</span>, good luck mate! let me know the results. I was thinking to switch to soil but still not sure if its worth it