I agree it looks like water splatter. But, your ph is too low as well. Above 6.5 and below 6.8 is best. 6.3 is too low. I like to keep mine at 6.6 - 6.7. Don’t waste your money on Co2.
Could be water damage, but like others said, your gonna have to post up a whole plant pic. My ilgm gorilla autos were super easy to grow and super potent to smoke!
Yeah lowest leaves tend to get ugly, no light, water/nutes spilled on them. I never see them as I keep the bottoms of my plants pretty cleaned up, makes for easier watering and not having to look at old ugly leaves. Remove those leaves and don’t worry about it, no biggie.
Yeah it’s for sure way up on the list. My friends and fam are all crying because I’m starting to run low on it. I sure hope the gsca’s I have going now can compare!
The really bad one at bottom looks like its messed up from touching soil. Tear it off lol no need for that ugly one in there.
Plant looks pretty good. Prob from water drops as others stated. If it happens to more leaves ask again for help.
Always check ph and ppm first with any problem and it is always best if making changes to do one at a time that way you figure out what changes what. If that makes sense.
Happy Growing !!