Mainlined Plant sick

This is my first grow. I am using fox farm ocean soil with smart pots. I have spent many months researching growing and have learned a lot . I have an 8x8 grow tent and humidity is approx 50- 60 and temps are approx 75. I pH all my water to 6.0. The one plant I mainelined started to get red dots and now the tips are drying, curling and turning grey . Should I flush the plant or is it lacking nutrients ? See attached pics. Last pic is how the other plants look. And the heading should say sick not suck

raise your water ph to 6.5 and they will better, whats ur run off? u might have to adjust your run off as well by to a flush restart to get it to 6.5

hibok said:

raise your water ph to 6.5 and they will better, whats ur run off? u might have to adjust your run off as well by to a flush restart to get it to 6.5

Click to expand...

Thanks Hibok,
I was going to do a flush tonight but I will test the run off first. I am just surprised that the other plants are doing just fine and this one is showing strange signs. Thanks for the reply

Looks like burn, some strains or phenos are nute sensitive and burn easily.