Nute deficiency problems novice grower

[asek]

This is the first large op i have ever done and i have been having problems left and right. I will try to be as descriptive as possible about all aspects and hopefully post pics soon

The room:
7-4x8 drain tables, top fed, 32 sites per table using 6x6 rockwool cubes
each table has 2-600w hps on either side of a 1k hps.

All lights are well vented

a/c cooled. 76-78 oF day, 70 at night

plenty of fans and fresh air, no co2 yet...

reverse osmosis filter for water

The Nutes:
I have been using general hydroponics at about half the amount the table says to use. I am also using cal-mag plus, and foxfarm solubles (open sesame, beastie blooms, and cha ching). PPM is just over 1250 and the plants are almost 6 weeks into flower. ph is checked daily and maintained at about a 6-6.2

I have used this same combination with tap water at my old house and never saw problems like this.

My first question is if it has something to do with the RO. tap water in my area comes out at about 350 ppm at a 6.6 so it would be harder to use.

The problem:
Plants in flower have severely yellow, almost white leaves. tips burn and curl in areas. some tips turn almost a brown-purple color and curl under. I originally thought it was a N problem, so i made guano tea to add with little to no effect. Flowering is still going ok, but there is a noticable loss in production. Its happening much more than i have ever seen before. i know the leaves will begin to yellow and drop toward the end of flower but this has been a problem since about week 4.

Could this be the RO?
Should i switch to other nutes?
is there something else i should add?

any kind of advice would be greatly appreciated

 

[FARM THIS]

i would start by dropping the ph to 5.8 or so and 1250 seems a bit low for that far into flower ..... i would def bring it up slowly and pay attention to the plants , and as far the nutes im not to familiar to all them as to i use almost all advanced ( had the best outcome with them ) i would think about switching your nutes as well

 

[amstercal]

Can you post some pics? What's your humidity? Without seeing them and just looking at your setup, maybe let your pH fluctuate a little more between 5.6-6.3. Allowing the plants to have a wider pH range will allow for more absorption of different elements. Also, constantly using pH up and down can cause problems with absorption by itself.
I'd hate to guess as to a specific deficiency without seeing pics.

Also, if you've grown this strain with these nutes before, then I'd check more for environmental issues... what's the pH and ppm of your ro? What's different about your room or how you do things since your last successful harvest?

 

[FARM THIS]

the problem with not using ro water is your 350 ppm can contain a bunch of one thing or a bunch of little things either way the best grow is done with ro ..... simply because you take it back down to zero which means there is nothing in your water and you add it all yourself , that way you know exactly whats in your water ! i know my ro is about 5 ppm and 7.0 basically neutral on the ph !