Seedling root question with pics

My seedlings were started on Jan 25th. They have been growing well in rapid rooters with pH 6.0 water. I have been watering twice daily morning and night when the pods are dry... not using a humidity dome. The water is treated with superthrive and 1mL/L 35% h2o2. There is also a heat mat which i hope is bringing the rootzone to 80-90 F. Ive had slow growing and diseased plants in the past and im trying to focus on perfecting pH and growing healthy roots, which brings me to my question. Where the roots begin to come out of the bottom of the pod they are nice and fuzzy, which means healthy. But on most, the tip of the root furthest from the pod looks yellow and schriveled... very hard to explain which is why i included pics. Im not sure if this is drying out of the root tips or normal growth. Im guessing something is fucked up so please let me know any opinions or suggestions.. for those who care im growing Bubble gum, big bud, northern lights, and mazarXafgan. so yea.... let me know if you seen this before... please REEFER to the pics

oh yes.. and when is a good time to transplant? thanks again in advance

they are dried up. need water in the bottom of your tray .. justa little.. if you have grooves in the bottom tray fill to the top of the grooves..

well i transplanted because something needed to be done.. Bout to throw them under the 400W MH and hopefully they explode