I understand your viewpoint, switching back to pro mix. Might not be a bad idea, if you aren’t willing to change water sources. (If the cause..) a peat-based medium like Pro-Mix might save you a lot of headaches, it naturally holds its pH more steady, so it won’t let the pH bounce around as much like coco does, especially when using well water. Bottom feeding with peat’s stability makes it easier to keep things balanced without constantly flushing or adjusting pH. Coco is great, but depending on method chosen to grow, could work against you in certain situations.. Just throwing it out there man, we all do what’s best for ourselves in the end. Path of least resistance.
Now to determine the cause, well, that’s a whole lot of troubleshooting on your end. Lots of potentials. I’m just shooting the breeze with what I think is most likely.
Edit……. Sorry.. lots of vodka
Have we had a convo in regards to peats ability for bottom feeding? Is it capable? I think the dry back thing could also be an issue, however top feeding less frequently than coco… idk I can’t organize my thoughts..
Your opinion is most valuable Brother, and I think I can rule out my water, it’s well and I’ve tested multiple times, it’s 28-40 ppm unless we get a hurricane, lol. I’ve used it every grow, so I think it’s ok. This was coco blocks, 11 lbs, same as I used last grow, same buffering procedure. I have discontinued use of any cal mag. Only difference was I didn’t have my usual perlite and this was garden center stuff. Perlite shouldn’t affect it unless there was something added that I don’t know about…. I’ll flush them with 5.5-5.5 tonight and give them a chance, I changed res out and dropped it to 5.6 and witty a half ammoniacal nitrogen Jacks formula, the 7-15-30 Finish I used end of last grow. Mabey eliminate some of the nitrate climb. Anything you think needs checked, let me know, I ain’t scared of a little work. I’ll report back……
I never buffer or anything but it’s different for my method. Doesn’t matter as much… but I do send several feeds through prior to planting so maybe that’s the same.. do you have the ability to flush with jacks, even just enough to hit 300-500 ppms? Your water has super low ppms, I see why you supplemented cal mag. Damn good water.
Edit
Just saw “flush nutes”
Crazy overnight change man.. what’s the temp of the res on average?
As long as it’s not miracle grow perlite you are good, and it shouldn’t change anything. Brick coco is always better than bagged.
heat… tomatoes Wth buddy, find ya some Mead or Summer Shanty or my go to Jack Black or local moonshine
Just fn with ya, but really Bloody Marys in the heat.
I mean where I’m from a lot of Clamato is drank but I can’t do it when it’s hot out.
Hangover cure with a plate of Chilaquiles yes
Anything salty, spicy, limey works great in the heat. Idk why, it’s refreshing. There is some science to back it. occasionally I get down with beer, like modelo, sometimes Busch, sometimes miller. Go to is whiskey. Maybe it’s because of all the Mexican friends/crew workers I used to be around but I got hooked on Spicy alcoholic drinks working hot summer days. They were sneaking cans on the job, I told them to buy the big fountain cups with ice and a straw and pour them into the cup. Drink on the job great spirits, dumb fun, beating the heat.
@Growdoc
MG includes extra nutrients I think it was @Lostgirl that discovered that
Ok, ran 5 gallons thru each of the bad looking ones at 5.4 1.2 EC. PH came down to 5.9 on them and I just fed the two that had no bad signs. Fed them Jacks Citrus as it has mostly ammoniacal and urea nitrogen, only 3% nitrate. Used this as it’s for acid loving plants and hope it will help lower the media ph and then back to Jacks 321 . We will know tomorrow…..
Feed in lower than usual going forward, only ease up a bit hitting flower dude. Maybe an appropriate media probe would help to avoid pulling core samples for slurries
I hate it but it’s all I could get at the time, usually get 4 cu ft bags from HD. I rinsed the shit out of it, and checked ppm to be sure. My ph is rising, most time MG will tank it…..
Tent res is 70.6 but these aren’t on a res, hand watering until they get healthy enough to turn pots on. The problem children are in big room, and just for shats and goggles, tent girls are on same perlite, rinsed well also.
Depends on what nutrients are involved man, slow release doesn’t necessarily mean a vigor rinse will get rid of it.. idk though. If you still have some slurry the perlite, slurry a rinsed perlite. trouble shooting
heat… tomatoes 
Wth buddy, find ya some Mead or Summer Shanty or my go to Jack Black or local moonshine 
yes
MG
occasionally I get down with beer, like modelo, sometimes Busch, sometimes miller. Go to is whiskey. Maybe it’s because of all the Mexican friends/crew workers I used to be around but I got hooked on Spicy alcoholic drinks working hot summer days. They were sneaking cans on the job, I told them to buy the big fountain cups with ice and a straw and pour them into the cup. Drink on the job 
great spirits, dumb fun, beating the heat.
trouble shooting