Nitrogen issues

Hi there, i am new to the forum. I have read a few posts and everyone here seems very helpful and nice. i wont say which ones but i tried 2 other forums and got nothing but rude comments. So hoping this can be my new home lol.

Anyway, This is my first grow so i choose to go with a AK-47 Sativa Clone and off the bat i was doing a handful of things wrong: Put clone in way to large of a pot, got soil that was too hot in nitrogen, watering to little; to often, not checking ph, but my tap water has been perfect so far, oh and i was also LST the plant. So a week into the grow the clone started to get yellowing on the edges and tips turned down.

I tried flushing the soil but it didnt help. The PH of the runoff was pretty low, 5.0 - 5.5 and no matter how high i PH up’d the water i couldnt bring the runoff PH up at all. In this time ive been doing a lot of reading, so i started to implement my new found knowledge. I transplanted the plant into the right size pot in a soil mixture of Dr.Earth Home Grown Vegetable Garden planting mix, Perlite, Vermiculite, and sphagnum moss; trying to loosen most of the hot soil off the roots, i then sprayed a light mixture of super thrive on the roots, put the plant in the new moistened soil that was watered with a super thrive mix and phd water. The plant is currently doing well other than 1 browned and dead lowest leaf, nitrogen issue still,

it is under a 150W HPS bulb because its what i had and im saving for an air cooled light hood, ballast, and all the ventilation. Currently in a room i just built, ill be posting in the forum covering the build, it is 4x4x6 room located in the corner of my garage closest to the wall where its always shaded outside. the room stays at about 74-82 temp and 30%-55% RH but right now were having a heat wave and its been 72-91 in the room. I have a 20" box fan blowing in the room all day and turn if off a little after the light goes out.

Any help i can get would be greatly appreciated. Thank you.

I can’t really tell by the photo, but it is older growth that is yellow?

You may wish to fill out one of the support tickets, with the link on the main support page, giving as much info as you can.

Have you ensured the new grow medium has enough nitrogen, and is at the proper pH?

Here is a better picture of the plant