Brown Edges and Some Curling

Alright, so i've run into another problem I can't seem to quite figure out again.

Growing a THC bomb indoors in FFOF Soil with Perlite, extra earthworm castings and dolomite lime. The plant is about 6 weeks into flowering. Temps are around 75-80 during the day and around 55-60 at night. It's under a 600W HPS about 2 feet away.

So I went out of town for spring break and I left my roommate in charge while I was gone. I watered on Friday before I left with .5 teaspoon/ gal of Fox Farm tiger bloom and big bloom. I also turned my light down to 50% when I left. I had my roommate water the next Tuesday with plain tap water that had been sitting out.

When I came back Sunday, I noticed the brown curled leaf edges and the brown tips only on the top leaves. I haven’t seen many explanations for this so I really need some help. The PH of the soil is about 6.8, so it's a tad high, but I'm not sure if that's what would cause this. Can anyone help me out here?


Thanks a lot everyone

It looks like a potassium deficiency, maybe from using too much limestone.

I didn't put much in and it's been in the same pot with limestone for 4 weeks before and it never caused a problem, could it be that delayed?

are you growing organic

nevermind didnt read post just looked at pics

ya i might back off the nuets a bit looks a but like a burn

I've only fed twice and it was extremely watered down. Could this really be a nute burn?