PERSISTANT PROBLEM, help me out!

alright well I got meeself the first problem I been havin in a while, I have brown necrotic patches on my leaves. I cant pin down what the cause is, Ive been using fish emulsion which has worked well. but about a month ago I started noticing patches on my leaves, starting from the bottom of the plant it has traveled up, I snip a leaf with that is far gone and it moves up to the next leaf by the next day. My fish emulsion is 5-1-1, I added some other nutes that were like 8-16-8 or something like that because the inner growth was very hearty but thinning and getting yellow the inner growth took off but these necrotic patches stayed. So I figured it could be a nute difficency...the spots get black/brown and they start on the edges then start blotching on the leaves. They may even start in the middle of the leaves sometimes I cant say for sure. My lighting is 600w hps just put it over from mh to hps for 12/12 its well ventilated 80 degrees tops, the light is a couple feet away from the tops. uhh anything Im missin? I've looked around and only been able to pull maybe some kind of nute lock out or something, Ive had a hard time diagnosing from charts and other threads. 70% organic soil 30% perlite.

My plants are currently in repair mode from the same issue. I am using the same soil as always but this time was different. I let the problem persist and was real confused about it for a couple of weeks, but I did not take any action until the issue was figured out. It turned out to be the ph of the soil it was sitting right at 5.5. Sitting at the low 5.5 made it difficult to impossible for my plants to use some major nutrients. Yesterday I added 1 ounce of dolomite lime to the soil, mixed in, and today the ph is at 6.5. In a couple of days (when soil is dry) I'll feed 1/3 dose of bloom nutes. Btw the girls are in their 6th week of flower.

If the ph of your soil is either too low or too high (good range for soil is 6.0-7.0) the plants cannot utilize the important foods they need and they get nute burn. This is, at some level, probably your issue. Check out the growfaq tab this is where I found the solution to ph issues.