sick red dragons

i have 11 plants, 4 strains, 2 are red dragons.out of all the plants, only the RD's are having these symptoms. on the worst one, half of ot's leaves are curling downwards and turning brown to yellow from the outside edges inwards. the leaves aren't grispy at all, they still "feel" healthy. it seems to only be happening on the the around the center of the plant.

i'm using sunshine mix#4 and using general hydroponics 3 part for nutes. i started at 1/4 strenght and the last feeding was at 1/2(2grow, 1 mcro, 1 bloom ml/L). i ph water to around 6.2.

i flushed 3 days ago and they still seem to be getting worse so i'm thinking it's a defiency of some kind. when i give them nutes, should i give a weaker or stronger dose? they are 2 moths old from seed and i switched to 12/12 yesterday.

what do you guys think?

i also wanted to mention that the red dragons drink about twice as much water than the other plants. i'm not sure if thats an indication of something. i doubt it though. also temps are 68 at night and 82 when the lights are on. the side of the room that they are in is the farthest away from the passive intakes. i have a osolating fan blowing air around the top of the plants so i think they should be getting enough fresh air. i could be wrong though.

i had 3 RD seeds but 1 didn't germinate so i don't want these 2 to die.

since they're 2 months old and only getting half strength nutes, i'm thinking they need a stronger dose but do they just need more of a certain nutrient? like i said, they're the only 2 plants that have this problem.

sorry about all the grammer and bad spelling in the first post, i was in a rush.

bump

one more thing to add. because the red dragons were getting taller than the rest so i did some lst using twine. the fan leaves on top and below the twine are the ones looking sick.