Leaf readers - I need your help!!! pics

Hello,
This is my 3rd grow.
I'm growing a few different strains, but this particular one I'm posting about is a Purple Kush clone (an Oaksterdam clone)
Fox Farms Ocean Forest soil
Outdoor grow
15 gallon container
Perlite mixed in for drainage
Tap water is used for watering, extemely alkaline, so I'm using a nitric acid based Ph down to bring the water just below 7 when I water the plants
I just found out I have soft water (below 30 ppm)
The plant is 1 week into flowering and it is 12 weeks old.
I have been using General Organics BioThrive and just recently, in the last week, Fox Farms Open Seseme
I live in California, in the foothills near Sacramento, it has been very hot the last few weeks, 100 plus degrees in the sun. The extreme heat always seems to stress my plants.

Anyway on to the issue. This strain has been very hard to feed. I give it just a little, and it gets rust spots on the leaf veins, and that continued to multiply on leaves until I flushed. I flushed it about 4 weeks ago. The new growth looked good, but it sure messed up the old growth. It made the old leaves wavy and weak. New growth did look good and perky though.

So fast forward a few weeks, I'm afraid to feed it because it seems to burn when I do, and I started by giving it just a small dose.

Now I am having my leaves yellowing and the tips are burning, and then the whole leaf will brown up and drop. There is a red tinge to the leaf margins, and the leaf tips brown and burn and the leaf is still green at the base of the leaf. (Wouldn't that rule out N deficiency?) I've had N deficient plants last year, and the yellow in a uniform pattern, the whole leaf yellows, not just the tips first. (See the picture I posted). So I brought a leaf into my local hydro store and he said to "hit it hard with CNS17...it didn't like the organic nutes you gave it." That makes no sense. It's SO frustrating, everytime I go to a store to ask advice (and I try several different ones to get different opinions) they tell me the same thing...WHAT kind of nutes are you using? General Organics? Dude, you need THIS!! They all just want to sell me more ferts.
So I don't think dumping a heavy dose of CNS17 would take care of it. I'm thinking it's a P deficiency or needs to be flushed?? What do you think? I have given it 2 small doses of Fox Farms Open Seseme early bloom enhancer, which is 5-45-19. The directions state to use it at first signs of flowers, so I figured I would, and if it was a P or K deficiency, that would clear it up. It hasn't. I have 2 Purple Kush clones, and they are both doing the same thing. Is it my water? I have also been suffering a Mag defciency, and I cannot figure out why. I watered with Epsom salts for a few weeks. Is there something (Ph or soft water??) that is locking P, K, and Mg out of my plant. it seems to have more than enough Nitrogen, it just seems to suffer from erratic deficiencies.
This was a weird year. I thought I knew what to expect after last year. The soil seemed to be running real heavy in Nitrogen, so I was afraid to feed it, and now I think it has P, K, and Mg deficiencies. What do I do?

I know that's a lot of questions, but I am very anal about everything I do with my plants. Ph adjusting all my nutes before they hit the containers, trying to move them out of the sun when it's 105 plus degrees, and I study the leaves for changes several times a day. I'm just at a point with this particular strain where I don't know what to do.....feed or flush?
Any opinions and advice are greatly appreciated. I'm a medicinal grower who cannot afford to buy from dispensaries, so what I grow is it for me....I need to make it work : )

Any other questions you have feel free to ask me. I think I covered everything but my favorite color and my mother's maiden name : )

Here are the photos, one is hard to see because of the extreme sunlight overexposed it a bit, but notice how the base of the leaf remains green while the tips start to yellow and burn. And n the other photo, look hard and you'll see the reddening of the leaf margin. The other photo is just a pic of the plant so you can see it's overall look and health.

Thanks everyone!!!! : )

have you tested your water p.h?

Yes, it is very alkaline.
I have been using a nitric acid based Ph down solution by Tecnoflora to bring it down to just below 7 when I water.

Anyone have any ideas?
Please?????

yeah dude it definitly sounds like a high ph in your soil or you have to much calcium present. It could also be sulfur defiencey. Sulfur defiency basically mimics notrogen def. If I was you i would lower the ph to like 6 and flush a minimum of 4 times the volume of water for the volume of the soil

Put 60 gallons through it?
That seems excessive. That's a ton of water.

I would put 50 or so gallons through it to wash up all the toxic salt buildup that may have accumulated and also flush your plants at least once a month, then flush again with a mild nutrient solution.

flush again !

It hasn't been fed really much at all since the last flush. Do you really think it has accumulated that much toxic salt buildup with just feeding it water mostly?
Nobody thinks it needs a feeding instead of a flush?
The guy at the local shop said it needs lots of ferts??? Not the answer huh?
Remember, I have barely fed this plant much at all in it entire life, so flushing seems like I would be wiping away the few nutes it has. Or am I missing something? Toxic salt buildup from other sources???

Thanks guys!! Keep the suggestions coming, even if you just chime in with a simple post of what you think the leaves are telling you....feed, or flush. : )

see water can lock up vital nutrients if it is over a certain ppm. i still would say flush and then flush again with a mild nutrient solution.

My water is under 30 ppm.
What could cause a lockup in that case?
Thanks : )
Should I be using a CaMg solution to raise the ppm?

u certaintly could use ca and mg because high saline water that contains sodium will lock up ca and mg. even though ur under 30 ppm on ur water u will still have dissolved solids (salt in solution) and that interferes with ca and mg uptake. but still make sure u fluh ur medium at least once a month and then again with mild nutrient.

I read in Jorge Cervantes book about water and ppm. He mentioned if your water has a low ppm count to use a CaMg solution to bring the ppm to around 150. Is this mainly for hydroponic applications, or does that go for soil growers too? I suppose without a digital ppm meter, I should just use the recommended dosage on the bottle.

good informative book. and he means ppm in both hydroponics and soil.

Nobody else has any advice whether to flush or feed? I'm surprised....

I'm thinking of lightly feeding one of the two and see what happens. If the problem continues I'll flush. But there seems to be a lot of yellowing on the lower leaves, and not enough signs of toxicity to flush.
Any ideas?