Extending a warm welcome! Welcome to the community @walkingstoner. You gave everyone some good info to work off of.
I am two new and even if my guess is right I wouldn’t want to steer you wrong. And you got some replies coming in! I see some typing. Good luck 
First thought was Cal-mag. The amount you are using is about the correct amount. Here let me tag a couple
experienced growers.
Have you check your run off PPMs? Looks like you may need to increase your cal mag I give my plants 5 ml.
Also your temperature is on the high side and humidity alittle low
First, welcome to the group!
Second, badaxx purple buds!!!
Next, I’m going to point towards possible VPD. The leaves inside don’t look to be affected, but the ones that receive the most direct light do. This could be from higher temps, lower humidity, and too much light. Your light seems fine, so I would try to drop temp down if possible. Those three combined the wrong way can make your plant basically release more moisture than the roots are sucking up.
Thank you guys for your input, I will start switching things around. And again thank you.
Welcome to the community! I believe @Borderryan22 has given you some good advice to get you headed in the right direction. 
Looks like you are showing classic interveinal chlorosis which to me indicates bumping up the C and Mg. You could double your dose without any trouble. I would also look at your runoff TDS to see what salt levels are remaining in your soil as a hungry plant can look like that too.
All of that said, leaves will deteriorate in flower and this is normal. Plant looks to be flowering nicely.
Welcome!
Have to agree with the above. The yellowing in between the veins is magnesium deficiency and the rust spots look like calcium deficiency. Need to know your runoff ph/tds to know what is going on. You can have a deficiency even supplying proper nutrients if you have lockout. (Improper ph/really high tds). Hungry plants tend to yellow more all across the leaf.
I’ve changed my vpd settings by lowering my temps to match my hum%, And I will be doubling up on the calmag. I will be updating the tds from runoff the next feeding. And aging thank you all for the help, This is truly a great community.
What is total ppm of this solution? I don’t use gh but this seems like it’s not concentrated enough solution for mature flowering plants. I may be wrong, but i feel like you should have something like a total of 20-30ml going into each gallon of water.
Before PH-ing it’s at ppm 400.
Yeah way low you need like 1100 ppms when in flower
I think this probably majority of your issues are.
