Bottom most leaves limp as a noodle?

My plants looked perfectly healthy last night. I just check them today and the bottom most leaves on one of the ladies are limp as a noodle. The whole plant is green, even the leaves that are limp are a perfect green color, and seem fine in every way except theyre limp today for some reason? Looking at the plant now it seems like its progressing upwards because as you go up the plant they get less and less limp, and stick out straighter and straighter. I never had this on my first grow, which was identical. The only think I have done different was increase the pot size, and simple LST(which I stopped doing 2 weeks ago so that shouldnt be a factor). Anyone know from experience what this is? View attachment 2514092

How often are you watering are you feeding them any nutes

I don't think its a watering issue, the whole plant would exhibit the symptoms if it was I believe. Just got back from the hydro store, and they agree that its probably ph issue because our local water, although being almost ph neutral, has a lot of dissolved stuff in it. They said that the plant pulls up the stuff in the water which changes the ph from being neutral or something. So I picked up a ph pen and am about to water and go from there.

Sounds like you have a good idea can you post your results. Im kinda curious now