What might be causing these issues? I’ll give you a quick rundown and what I think it may be. These are all autos sitting in some Stonington Blend Platinum Growers mix and are currently on day 26. Three days ago I top dressed them with 2 TBS of Stonington Blend plant food 5-2-4 with lobster, kelp, and worm castings. The issues were already present before the top dress. I was watering everyday for the first couple weeks (which I now know might be over doing it) but only 1 cup per plant. I started watering deeper close to a week ago with 1 QT per plant every other day. I also make sure the soil is dry with a finger test and my moisture meter before watering. I think the issue is that I’ve been using RO water without putting Cal-Mag back into the water. It’s my first real grow so a rookie move for sure. I believe it’s a deficiency in cal and mag. What do y’all think is going on? Also, my top dress has calcium and magnesium in it so shouldn’t that help correct the problem? It’s only been 3 days assuming it can take up to a week to see adjustments? I have been keeping the water Ph between 6.3-6.7 and the soil ph is about 7. The light is about 2’ away currently. Their next drink is gonna be some delicious thunderstorm rain water. I collected 15 gallons or so. Thanks in advance fellow growers!
My guess is a ph issue what’s ph run off out the bottom ?
Looks mag related to me
I keep my water at 6.3-6.8ph and soil is 7 currently. I can test next watering.
Agree with the pH issue, Magnesium has interveinal yellowing but no burnt leaf margins (Potassium?), looks that the plant has enough feed but it’s unable to process it … 
I’m having problems myself atm so take my advise with a grain of salt.
If your using ro water which has little to no minerals to use as a ph buffer then your ph will jump and drift all over the place. So im guessing your not feeding the ph that you think you are. Adding just a few ml of calmag BEFORE adding anything else to the water will give you a more accurate reading.
For that reason I’m saying ph issue
With ro you really gotta find a way to get proper calcium. Everything in your diagnosis was pretty spot on.
I ordered some buffer today to calibrate the ph tester I have to be sure it’s accurate, and I also now have some cal-mag. My next several waterings will be with rain water that I collected. Is there any need to still apply Cal-mag to the rain water?
Depends rain water can test funny I have to ph down mine and ppm is around 130 .
I’ll definitely need to adjust PH, but didn’t know if I needed cal-mag being that it’s already present in rain water.
I am using rain and snow. I have been adding cal mag each time. not sure if i should. My plants may be over green. Just wondering are you still using rain and have you dialed it in?