Rob spaketh thusly with great wisdom:

When I used Dynagro, I always had raise my pH. I used 10N NaOH
(sodium hydroxide) - but it didn't take much. Most people probably
don't have access to pure NaOH, but lye would work. Or you can just buy
the various 'pH-up' and 'pH-down' products on the market.

Sodium hydroxide is very effective at raising the pH; potassium
hydroxide would have the added benefit of adding potassium, which plants
use at a much higher rate than sodium (if they use sodium at all).

HOWEVER, sodium hydroxide is very dangerous- toxic, caustic, you
name it. Drain cleaner. With this in mind, use the proper safety
precautions (gloves, eye protection, shoes and long pants) if you use it:
Red Devil Lye. Pure enough to make soap with. A solution of this may be
added dropwise to your water to raise the pH.

Solutions should be stored in tightly sealed bottles. The solution
absorbs carbon dioxide, reducing its strength over time.

-AJHicks
Chandler, AZ