Rusting leaf trouble

So, this plant started with its bottom set getting this rusty color to the leaves starting on the bottom leaves and it slowly made them so brittle they just chip off. I didnt really care that much but now I see it starting to climb her!

She doesnt mean that much tbh, its a rando bagseed that I threw into the pc case to try it out before I planted one of the low ryders I ordered in there. The PH is sitting at like 6.1-6.4, watering with many days distilled tap water, and as for nutes it is in a I know I know dont hate me! its in a low fert fast root starting MG soil. I do have one of the lowryders going now and in a few days I should be able to tell if its the soil overnuting or something but it really doesnt look like that to me O.O looks almost like the plant is rotting?

I did go finally look up a hydro store in my area and picked up some FF ocean mix so I will be using that for the 2nd low ryder seed if this one poops out =P

Also I havent a clue why the leaves are curling so bad. There is over 100w in the PC case so thats definitely not it...

Any help is appreciated!

I am willing to bet it is a magnesium deficiency. Notice how your leaves are folding up. Foliar feed the plant 1/2 tablespoon of epsom salt to 1 quart of hot water (not boiling). Then spray it on top and bottom of your plant's leaves.

+1 on om3 thats magn... feed it but i would say its lacking some nitrogen to as that cup is getting quit small for that plant your asking for more trouble............

I dont see any picture?

Okay thanks for the help ^.^

As to size im not actually gonna let it get big =P it was just a tester for its environment/water/soil so that when I plant the real one I know what to fix before hand. Which clearly, I will need some mg haha!