Advice wanted, pictures included

400w HPS, 3'x2'x5' cab, 2x6" clip fans, over 400cfm cab exhaust and 250cfm light hood exhaust, tops are 4"-12" from glass of hood, canopy temps 76-82degF lights on and maybe 60-70degF at night, base of plant temps 60-70degF lights on/off, RH 25-40%, Fox Farm nutrients (tiger bloom, big bloom, grow big) with water ph'ed to 6.3-6.6, the ppm of our tap water here is in the neighborhood of 60, somewhere around 4 weeks into flower, first time grow - 2 plants (Monty Python both clones from same mother).

First sorry some pictures aren't focused well and some are with HPS running. It's awkward to take pictures with the camera I'm using and the position of this cab inside a closet. I have a few concerns. What kind of deficiency do you think is going on with the brown/rust colored marks on some of the leaves. They aren't necessarily oldest of growth nor newest growth. Only some leaves on both plants. How about the white tips on the main two colas? Bleaching from light? Only a 400w HPS, 4" from glass so like 6" from light bulb... Biggest concern is the purple/dark leaves on the buds. It's the tips of the really small leaves growing from the bud but not ALL the buds maybe half or so, is it from the temperature change day/night? Or is it fucking mold??? I will stab someone.

Thanks!

That just looks like a bleached top in the second and third picture not 2 much to worry about light might just need a little adjustment. for the mould fro looking at the picture i cant see any signs of moulding so no need to worry 2 much about this . the purple on the leaves can somtimes be caused by temperature fluctuations but u seem to be on top of ur temeratures so i dont think thats the case here . But as i said no mould so happy days . I hate fucking mould lost a really nice fat top nug from a recent harvest over mould but i was happy it didnt spread to the rest of the crop

MrGhettoGrower, please read all of my post before you reply to it. Furthermore, yellowing occurs at the end of plant life cycle, which is not what is pictured above. When you just guess, it's the opposite of help.

Bubbles, thanks for the intelligent reply. My night temps may actually be lower, maybe down to 55 degF, which makes it nearly 30degF difference. So I hope the dark coloring is from that.

Does anyone know if the brown/rust color marks on leaves are from a nutrient problem? Since our water is 60ppm initially and I try to keep to the fox farm feeding schedule, maybe a Ca def?

For a newbie your grow looks fucking great , chill and relax there is no need to stab anyone at this point .. Mold is nonexistent from the photos shown ...

A perfect grow is bull shit and always a cameras illusion as often the healhiest of plants can have a fucked up leaf now and then . I dont see sick plants as what you see is typical with a light so close, the leaves curling from heat and fading like so .. Your going to need some Cal/mag if you want to keep your tops that close to the bulb and alot more air flow ...