Leaves turning brown and dying

As you can see, some of the leaves on this plant are turning brown and shrivelling up/drooping.
Anyone know what this could be?
I've used nutrients on it once (less than the label recommended) and I originally thought it was a nutrient overdose, because it had only happened to the one plant I had used it with.

However one of my other plants seems to be showing the same symptoms on one of its leaves and I'm really at a loss for what to do..

how old is the plant? what kind of light? how often do you water her? when did u last give her nuts and what brand and how much? what kind of soil is it, brand as well?

About a month and a half old,
sunlight,
water when the top soil seems dry about an inch down,
gave it a tiny bit of miracle grow 6-5-5 plant food about a week ago, diluted way more than the label said just in case,
the soil is just usual compost from the local garden store I guess, not quite sure of the brand but it wasn't anything more than normal compost.

I'm a bit worried because the lowest leaf on a different plant is showing the same symptoms as of today,
The browning on the plant in the pictures started yesterday.

Well it really looks like nuteburn...you aren't supposed to plant plant's straight into compost...you are supposed to mix it with soil and then plant the plants in it, or add a layer of compost to the bottom of each pot...

If that's the case how come they've been fine with the soil they're in for over a month and this has only become apparent recently and on only two of them? I think the compost might have been pre-mixed with soil anyway, because it's basically planting soil..

I originally thought it was nute burn, but one of the plants showing symptoms hasn't even been nuted at all..

It looks like your ph might be WAY off, i would get a soil tester and check it out and let us know. No more nuts and i would say flush her. But i would get a tester to see the ph because my bet is that si the problem that and nut burn

I was using usual tap water so that would make sense,
should I leave the water to sit for a while to let the chlorine evaporate? I only learned this recently so yeah...

If chlorine is affecting the pH what should I do to change it?

Get a soil tester, and yes let the water sit out for 24 hours u want the soil ph to be 6.5. i have seen tap water ph of 7.8 ( It happened to me )