Need to know what my problem is, leaves are curling and turning yellow, brown, & red

[Deepsuthern]

hmm...ok im not positive on this but i have a feeling that it may be from a lack of phosphate... or too much? I know that there are adverse effects on a plant if you over-fertillized but i can't remember what nute does what side effect... when's the last time you checked your ph level? my gut tells me it should be around 8