Help Diagnosis! Plus Rep :) brown spots on my babies :(

hey guys check out the pics this is my set up 400w hps few cfls a stanley blower as exaust fan passive intake and small 6 in fan with home madeco2 as you can see in the pics they are developing brown spots which is killing off the lower leaves i just started watering them with nutes 2 tblsppons per gallon big bloom andnot all plants are affected i have them about 14 inches from the hps light any help anyone?

if you need any more info let me know

try a flush then start back off with about1\4 of what u were using when u see a change in the plant health ofcoarse then slowly work ur way up untill u and ur plant are comfortable with the amount u are using

y are u flowering them anyways thay look to small but that might just be my opinion

they are not in flower they are in veg 20/4 i just recently put the fan in there and i just started the nutes when i seen this problem start to develope

any other idea on what it could be?

most likely a ph problem and nute lockout, either that or nute burn. find out your soil ph before flushing, if your ph is fine, it can either be salt buildup, or nute burn. either way flush the soil and use weaker mix of nutes. if your ph is off just adjust the ph of your water accordingly for next watering.

BROTHER trim thoes leaves thats damaged , flush,and start nutes again and monitor the leaves that are left .. i never seen such tho so u can try this and see if it betters

will do thank you so much

definatly Phosphorus deficiency, lower ph to5.5-6.5 so is becomes availabe for uptake.

Not a phosphorus deficiency.

Definitely pH spotting. Look it up.

You need to know your pH. I agree, flush, and balance. The plant will be fine in the future so long as you keep an eye on the pH.