RQS MIX

Transplant is good lay it in the hole or you could also top feed it just put on top fluff into soil then it will activate and mix during watering. Depending on your product there might be a solution mix available. But if your transplanting anyway just do it then

Roll stems between fingers a few day prior so plant forms a knot. Then hst it by rolling area right above the knot so it will rest in it as it lays. Using the knot for support

no pics so tough to say.. but could be light-related. depending on where your thermometer is, the temperature more directly under light could be higher, in which case heat can be a potential cause too. 3x2 tent? roughly? 300 watts is a lot of light, especially at 17" from canopy. unless your pushing co2, that's probably a good bit more than you need. so a little more distance wouldn't hurt. plants look healthy, otherwise in the diary pictures, so just a matter of observing.

Could be a phosphorus defficiency. Before doing anything, I would check the runoff waters ph and ec levels. Make sure everything is in range for the substrate your using. Make sure it isn't a lockout issue before increasing your bloom nutes.