weird spot on leave

im not a professional.. I have been on this forum for yrs now.. sometimes when i do try and diagnose a problem i dont seem to come up with a conclusion.. so maybe someone can help.. before it gets worse.. i can say on a younger plant the edges crisped up and dried out.

im using regular potting soil.. I water with tap water. sometime bottled water. and i have a ph meter coming in the mail soon. i try to water every 4 days. i would say it does have a light green look to the plant.. so maybe it need to be hit with nutes.. bt until i can read what my ph is Im smart enough not to add nutrients before i check ph.

As for my water i try and let it sit out for a day before i actually use it. dont know if that helps..

hmmm No one ? the leaf is now yellow ? any clue for this. leaf is geting worse. seems crisp at the touch and seems to want to fold up.

how big is the pot? maybe time to transplant into a bigger pot.

Root bound plants sometimes develop strange brown leaves/spots
that pot looks a little small for your plant

bro this is a ph problem.
i'm not an og, but ive been doing this 5 6 years and i will tell you from personal experience and looking at the pictures this is caused by ph being off.
if you can spare 7 bucks you can get a test kit.
very easy to use.
i actually have a digital one, but it took a shit on me so i been usin this for like the last 6 months.

I figured it was ph... No nutes was given. And I transplanted her (hopefully ) last 1.5 week ago into that pot from a 1 gal. If need Ill put her in a bigger pot..and yes the leaf has gotten worse.. luckly i will be buying a ph tester. thanks for the help..

i have a question.. can any one point me to a column or show me a pic of ph being to low, and a pic of being to high.. for i think my ph is low.