got a few yellow leaves on bottom of plant need some feedback

bagseed and ffof just started addin nutes but i am stopping now cause of this pretty sure nute burn but i need more opionions!!!! plants bout 3 to 4 weeks water only when they need it not every day 18 6 cfls dont have a ph meter yet but i buy gallon water jugs at the gas station in hope that the ph is better than my tap!! i flushed it today pretty good so im hopein she will bounce back what yall think just nute burn?? temps avg 80 85

Looks overferted to me. The leaves trying to roll up and egle claw. I hope your flush worked out. I'm not sure but I think bottled water pH comes in around seven.

Just use plain water till they come out of it.

thanks for the advice buds happy growin yall