The charts vary I myself shoot for 7.0 or under...one chart says lockout at 7.0 In my experience this is bull....I've never experienced lockout when water was neutral.
But if ferting the water check b4 and after fert to see what the fert is doing
A lil lime as a buffer in the soil is a good thing esp. outdoor. IMO
top dress with lime don't try to tea it up in a feeding.