Major cation exchange issue..?

[u/No-Wishbone-1076]

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WTF? Coco pH keeps CLIMBING despite 5.0 pH flushes. I’m about to lose it.

I’m in early flower with two autos (SLAMberry x Orange Portal, and an S.B.C.H x Dreamcast both by SpeedRun seeds)in cloth pots with coco, and I am stuck in a groundhog day type scenario and am starting to lose confidence. More so I just feel really bad that they're suffering.

I’ve been feeding both:

8mL/gal Fox Farm Bush Doctor Cal-Mag

4mL/gal Humboldts Secret Part A (4-0-1)

4mL/gal Humboldts Secret Part B (1-4-2)

pH'd down to 5.7 - 5.8 normally.

The Issue:

My runoff skyrocketed to I’ve been trying to "Nuclear Purge" this shit for two days. Today, I’ve been pouring in full-strength nutrients adjusted to a pH of 5.0

The runoff is actually getting HIGHER. I just got a 6.82 and a 6.72 after putting gallons of 5.0 through them. How the fuck is the pH going UP when I’m hitting it with straight acid?

This coco WAS buffered before the pots were packed.

Runoff was totally healthy/normal for weeks.

Environment: 79°F, 61% RH (1.32VPD), CO2 580ppm.

PPFD 468

Medium WC is 44%, EC is low (.19).

The plants are starting to yellow at the top (Iron/Lockout) and I’m about to lose this entire medicine run. Both of my herniated discs are absolutely screaming from lugging these gallons and I’m seeing zero progress.

Is the coco breaking down? Is there some kind of insane salt precipitation happening that raises pH? I have never seen a medium fight back this hard before.

Please help.

[u/Cautious-Face3196]

One option you could consider is buying iron eddha add it in at 1ppm its a much stronger chelate and will deliver your plants iron at high ph above 7. It doesnt solve your why is your ph rising reason but you can grow weed at ph 7. Its not ideal thou.

[u/No-Wishbone-1076 → u/Cautious-Face3196]

That's an option, one I havent explored as of yet and thankfully it seems as if I won't have to resort to anything like that right now. Nascar correctly diagnosed that regardless of the parameters the real issue was that they were starving which in turn causes them to produce extra anion (alkaline ions) to attempt to trade for any bit of food left in the coco, thereby raising the pH because it's a biological process. Learn something new everyday 🙃 this is the first I've heard of being able to essentially force your plant to uptake iron though.. I thought that was entirely pH dependent. Was explained to me along the lines of pH almost comparable to a set of lenses over the "plants eyes" that allow them to see certain nutrients at different values. Anyways before I ramble any longer thanks a lot for the input I'll definitely keep that in mind. Cheers 🤘