No post sale support, no response regarding paper that does not change color with pH value (it appears untreated with indicator).
Bought narrow range pH paper that does not signal color in buffered nutrient solution. Tested in other solutions within the pH range as well to cross check.
Emailed Micro Essential, following up many weeks, also wrote on their contact form just in case my emails were getting sent to spam.
Basically, the product has a problem, and they will not respond or help me at all. YMMV. Also they make you order above a minimum quantity, so you are out whatever that costs.
I use other ranges of Hydrion paper to check nutrient solution, but quite frankly this interaction erodes my confidence. I welcome a response from the manufacturer, but honestly, it should not have to come to this.