Yeah, the Ph may be creating an issue. To check it, you can buy a Ph meter pen, they range $20 to $100 for the industry standard. Another way is to use a drop from
General Hydroponics. It changes color based on Ph, usually runs $10. You can buy a Ph up and Ph down product from the same company, which I recommend, but you can also use a variety of home based methods / ingredients. Room temp water is generally good, ideally between 65 and 75 I think is the target temp for water.... I'd have to double check that though.
Are you using coco or soil? They will have a slightly different target Ph for both input water and within the root zone.