There have been concerns about pH and bloom color. I was thinking that I had never heard of this, but then for many years, the mixes weren't this peat stuff either. Maybe that's why I'd had no issues in 3 states and varying types of water.

That may be a little bit much on the fertilizer though, but I'll let someone else speak to it. I was using 1/4 strength every time I watered and it was too much.

Diana

There is an article I found: "But My Trays Were Clean!" Micronutrient toxicity: fertilizer, soilless mixes, and pH testing. By Barbara Pershing
There are pictures and descriptions. I don't know if any of it applies to this problem but it is an excellent article. The article came up from Google as Part I Part II PDF files.

This came up in the podcasts too. According to her, there was no cure and she trashed her entire collection. I don't really know a great deal about it but I'd sure look into every other issue first! :)

(Sometimes it seems like there's a new panic that comes along just when you think you've settled down from the last panic...)

Diana

Diane
I grew beautiful plants in water PH 7-7.8. I think this would only be a problem if the PH of the water is at least 8 or below 5.5. I am conducting experiments with PH soil meters and PH water strips. I know my plant's blossoms turned white, then purple from an original blue. The new blossoms are waxy but I would have micronutrient lockout from high PH. Maybe same problem, maybe not. I am researching. I will post results in a week or so.
I think any water that is under total dissolved solids 500 ppm, which mine is, doesn't need a filter. As you noted, simple may be preferable to fancy when it comes to fiddling with soils, water ph and such I have killed more than one plant with kindness. Fertilizer burn is also a suspect.