Help! 44 day's into veg and soil ph is too high/rising?

I'm reading that 1 cup of white vinegar to a gallon of water can help lower the acidity of soil, is this true? will it hurt my plants? I'm having what appears to be a boron deficiency, my hanna instruments meter crapped out on me after not being maintained for so long so I got stuck using ph drops this grow. With no real way of getting a good reading on the soil I went and bought one of those meters you just stick in the ground which im getting a reading of high 7's.

My Grow:

Promix Hp: Added a tbsp. of dolomite lime per gallon (as per what I was told to do)
General Organics (Go Box Nutes)
Mykos in the transplant holes
600w MH Conversion Bulb
Temps sitting between 20 - 28
Rh of 30 - 40 currently but was significantly lower at first
My water is just tap water that I let sit out for a few days to evaporate the chlorine then I ph to 6 - 6.5 according to the General Hydroponics ph test solution.

They've already begun to show sex about a week ago or so with 3 out of 4 of my plants being female so I don't wanna do any extremes that are going to stress them but they've already been showing these symptoms for a few days now.

Any help is greatly appreciated.

Anyone? before I start trying to over correct and messing sh*t up more. I could use something chemical to drop it but trying to stick to organic as much as I can but I need a ph change pretty quick rather than gradually.

iirc I read somewhere you should never have too radical/sudden of a ph shift -- even when making corrections I'd have to assume? I'm thinking it led to shock from that alone but it's just a thought from various trolling in forums over the years.