Help! Any Advice or Comments

Turned lights to 12/12 thiry days ago , 25 plants under 4 1000 watt hps.planted in ffof soil running heavy 16 nutes at 800_ 900 ppm with ro water with at 6.5 ph with added cal mag, carbo load pk 13/14, pro silicat, great white, dimond nevter, cannazyme.

Just curious on any comments,.also getting a few leaves that are turning yellow and curling up at the tip and turning black, but inly on a few of the plants

Looks like you got a magnesium def, check your soils ph to make sure your not getting a lockout. and due to the fact your using RO water you wanna supplement it with some kind of calmag supplement. Also when adding you food to your RO water most likely its gonna drop your ph of your nutrient solution too, make sure your testing your waters ph after you add your food. Ro water is touchy, you can add 3 drops of ph down and it wont take it down much and on the 4th drop it can make the ph drop drastically... kinda wierd?? Your ppm seem a tad on the low side too

Well I flushed , gave cal mag checked ph at 6.6 to 6.4 which I know is to low, added dolimite lime. So well see , watered tonight at 1200 ppm, took a ton of ph up to bring it up .3 ,it was a 40 gallon tank.but litterlly took 1/4 of the bottle,

Don't use too much of the ph stuff, I'm pretty sure it adds tons of salts to your medium. Also it wont change your soils ph just running straight ph'd water thru it. What kind of lime did you add? I also read somwhere that silica lowers your ph too, I would try cutting that out..

I have heard silica lowers ph as well And is a bitch to raise the ph in the tank. I had a 6.3 with full tank of nutes so I added ph up