help with confirming an issue and treatment

[flplantguy]

As you can see in my photo my (newly planted this year) Bentinkia condapanna has an issue. I'm thinking based on research here that its high pH water (8.5 to 9) causing iron deficiency even with it in the irrigation water pretty low in TDS (250 or so). It has slightly improved with rain over irrigation this past two weeks as can be seen at the base.  Can those in the know confirm and advise on best mamagement/treatment?  I use a granular fertilizer thats the basic one from the big box store until i see these issues and make the nest change. No other problems in ground but a few in pots had issues pre fertilizer.  I also learned that M. darianii is sensitive to salts/pH/heat(?) and i repotted, lost the granular fert, and started using rainwater for it. It seems to be a bit better now and has started growing too.  My first idea is to buffer with an injector system, but i am no chemist and if there is a soil based solution for high pH water i would rather do that.  That being said whatever is best for it i will do regardless they are both personal favorites. The others are all fine or thriving (small issue on the potted neovietchia storkii pre fertlizer too) so its soils for the condapana and missteps on the others. Thanks for the advice in advance!

[kinzyjr]

@flplantguy Probably the easiest solution to implement is to get a small water distiller and use distilled water on the plant.  If you want to add a dilute fertilizer to the mix or maybe a drop of vinegar per gallon of water to get the pH a hair below 7, you could try that.  When I run the distiller, I end up with a crust of minerals after it is done that needs to be removed with either citric acid or vinegar.

[flplantguy]

So i went back and looked at my water test data from before and did some comparing with a tester that handles pH, conductivity, and tds.  The conductivity and tds are low, and THAT meter says the pH is 8. Salinity is 0.  It may be alkaline, but theres not much there to adjust.  Could i be not fertilizing enough with a fast grower? The potted ones i fertilized all did better, but not this one as much.  Hungry and needy is ok, i love to fuss, maybe ill try a foliar spray or liquid feed it tomorrow and see what happens.  The older fronds are happy still, but the oldest is dying off while moving its goodies up the chain.  No tip burn either, so a feeding won't hurt i dont think. They are due this month anyway im just leery of the granulars now.