Calcium deficiency or PH problem?

https://duckduckgo.com/?t=ffab&q=soil+ph+availability+chart&iax=images&ia=images you can find numerous references that show Ca will be fine at 7.6. soil can buffer and help regulate pH. This is not news, either. The more 'shit' in solution, the tougher it is to move the proverbial needle. i.e. RO will be more susceptible to ph-drift than 300ppm tap water. That does not make tap water better, it just is causality of this relationship. if there's 10x more things diluted and have the same pH, the large amount of solutes makes it more difficult to shift the pH. https://pressbooks.online.ucf.edu/chemistryfundamentals/chapter/ph-and-poh/ h30 and oh concentrations are outcomes of acids/bases dissolved in water. they are used to calculate pH. h30 and oh will cancel out and results 2 (molecular ratio) of h2o. this is how acids and bases neutralize each other. After that, the log of what remains after canceling each other out is the pH. or, negative log, whatever the equation says, lol. specifics are not needed here, just the gist. the point is you can have the same pH with drastically varying amoutns of solutes and if the solute levels are lower, pH drift is easier to occur. it takes less of 'something' to throw it off. products of microbes or things you add with water etc.

A pH of 7.6 will make the calcium unavailable,............max 7.0 pH for soil. Your plant also has a major phosphorous deficiency. How can soil "compensate" for anything?

Some really bad chemsitry knowledge here. Cations do not readily bond with each other. They would repel each other. cations bond with anions, not each other and not when they are 100% disassociated in solution. They are in ionic form in that context. They would bond to different sites, not similar sites for the same reasons as why they don't readily bond with the same type of ion. https://lawr.ucdavis.edu/classes/ssc219/biogeo/fig13.htm -- doesn't fully explain this specific thing but touches on enough relative topics. beware of science lectures from someone with a terrence howard video professing that "1x1=2", and a bunch of other psuedo-science nonsense. the general answer might be right/memorized, but teh explanation is not accurate, lol.

Not calcium symptoms. Unlikely pH, as you'd typically see more than one thing coinciding. This looks like a clear-cut nitrogen deficiency. late stages have those dead areas too. if the pH of the soil is 7.6 (or is that runoff measurement?) would mean the soil is not properly compensating, because it has risen quite a bit, i would expect. 7.6 shouldn't lock out N or Ca. studies indicate that you likely didn't reach full potential for growth rate, though. A slightly acidic substrate is better. So your tap adds 66ppm of Ca and 17ppm of Mg. This alone would not be enough, but you also have 'something' in the soil that is providing this stuff right? These values alone would definitely end up with deficiencies, eventually. Mg symptoms are visible 30+ days after the problem exists/starts, but Ca issues would be visible sooner. with soil you need trial and error to understand if it is providing enugh of 'everything' 2-3 months down the line and how much you have to supplement it. the plant and reality dictates this not some preconceived beliefs.

Calcium and magnesium work in concert within the plant, and so for many years it was assumed you had to ensure a good ratio of calcium to magnesium in order to get good growth from your plants. We now know that it’s both simpler and more complicated than that. The ratio of calcium to magnesium in the soil isn’t important, provided there’s enough of both for whatever is growing. However, too much calcium can cause a drop in available magnesium. The two get along and readily bind to each other. You may well wind up with a magnesium deficiency if you go too hard with a high calcium-to-mag ratio. This is especially true if the weather has been erratic – plants draw calcium from the soil in water, so if the weather has alternated from very wet to very dry, it interrupts that uptake. The soil can only compensate if it has CEC cation exchange capacity. Tap water contains 400ppm of calcium, magnesium, zinc, chlorine, and whatever else makes things go alkaline, so it's normally above 7. This is constantly adding Anions that bind to Cation sites in the soil, which once CEC is full, the plant will no longer be able to compensate for nitrates and the medium will drift. Makes good to keep track of an organic soil EC and re-fertilize once EC drops below a desirable threshold, then It's just water until she needs a top-up, replenishing any deficiencies as they arise.

I think PH maybe at play here as well. 7.2 is a bit on the high side. I'd aim for anywhere between 6.2-6.8 The problem with hardwater is the Ca and Mg are normally in the form of Calcium Carbonate and Magnesium Oxide, these compounds are hard to breakdown and take time. Its not avilable to the plants right away and likely won't become available. Strong acids can break the bonds easily but then that PH is not great for roots. I find citric acid is great at descaling shit and helps it become more available but it does not last long so PH drift is a thing. the amount of chlorine/chloramine in tap water is so low and I don't think would be an issue. You can always denature it by adding in vitamin c or asorbic acid and waiting a day for it to off gas. I grow my entire deck with tap water when the rains don't come and never have had an issue with it. and it gets that water 90% of the time. I think as a quick fix you could feed it a bit more and try adding in a readily available CaMg supplement. Soil does manage a bit of its own PH with the microbes that are in it. but its not always 100% its harder in containers vs open plots.

If the ph is 7.6, best bet is, THAT is the problem. It's best to keep that at around 6.5 when you work with soil. No, the soil does not compensate for that. Not all of it at least. (unless you are actively vermiculturing) Measure the ph of your feeding and measure the ph of the runoff to verify this yourself. If your feeding is 7.6, your runoff is perhaps 7.1. That would generally be too high, leading to issues like nutrient lockouts because the plants has difficulties up taking nutrients the higher the ph. Get the ph issue regulated asap. Don't miss one feeding. Don't let your pump system stand empty (or "Off") again. Give her some tender loving care and she should bounce back in about a week.

it may be a chlorine/chloramine issue especially from

You need a ph meter to get the ph lower 6.5 is optimal for soil, this should be step one, yes in organics it should for the most part ph it self but still optimal is to ph where it can absorb all nutes at its best, also second thought is it’s under fed, lower leaves are deficient in nitrogen and all too leaves are light green, give her food!