Brown fan leaves with dying tips also leaves curling down!???

I'm a little over a month into flowering and seeing some of the bottom leaves turning a rusty brown, setup- 400w hps, 3 gall grow pot using fox farm nutes , temps from 76-60, I'm watering every 3 days about a gal of water each time also I'm using tap water with vinegar to lower the ph. Here's a few pics ... Thanks everyone

Please help guys !!!

Hello anyone??? I thought this forum was for help??? Where is it at???

idk man but my seedling is doing that, but im using old used soil and it was organic which I had trouble with in the first place im thinking a phosphorus deficiency

Give it nutes man, its lacking

Is it a must that you lower the ph? I personally wouldnt mess with it unless you have to, if you get it to high or low it will stop taking nutrients and youll run into isues, whats your ppm? Id double it right away and stop using plain water your flushing out the nutes when you do that, im confident many on here would dissagree but the pics say alot, i hope it gets better for you

Sounds like its lacking nutes thanks everyone

The regular tap ph is around 8 so I have to lower it right?

have you measured the PH of your water or are u just guess its 8

The leaves are probably just changing color do to the low temps.

I have a ph testing kit but its the kind u drop dye in.

I'm going to feed her again and see if there is any improvement, thanks everyone for the advice