1 Month Veg 3 OG Plants NEED HELP MASSIVE PLANTS

I am growing 2 og x grandaddy and one la master bubba. I am using forfarm grow big and big bloom and my nutes ppm's are around 800 and ph around 5.9. I do not understand why they are turning brown at the tips. Please explain to me. Sorry for low quality pix.

Could be nute burn. Over feeding. Try to not keep the ph 5.9 constantly as it would be hard.

looks like nut burn or u need to add some cal-mag. Are u using RO water?

yeah looks like nute burn. id cut back on the nutes and slowly add more till they can handle full strength. im using foxfarm trio also. im in first week of flowering and my ppm is 1330. the plant is about 7 wks old. at 5 weeks old i was at only 500ppm. but thats just me. go to straight water for a couple days then re introduce nutes. good luck

those leaves don't look kushy to me.Must be gd leaves,never seen a gd leaf.

Yes i am using RO Water and i have lowered the nutrients to 500 ppm.

I am going to use straight water for one day and then ad a 600 ppm nutrient and start using open sesame.

I was wondering if my water is 380 ppm out of the tap should i subtract that from my reading after i give nutes?