Ph flushing problem need help

[Shields1898]

I’m using royal gold kings mix in a 5 gal pot in 4 week flower and I have a 4.5 ph run off and I just flushed it with 10 gals and it still coming out as 4.6 ph has anyone had this problem? Thinking about using another 5 gallons to flush right now

 

[Shields1898]

So 15 gal later 4.85 ph

 

[growsince79]

So 15 gal later 4.85 ph

You probably need to add lime.

 

[Edinburgh]

Bakeing soda will raise your ph but u must be careful, the last 2 weeks of my last grow of 3 bears i noticed something wrong first thing i did was check ph it is usaley 6.2 somehow it went down to 5.3 and 5.5. I flushed plants and gave a bit of baking soda and got them back up to 6.2 an old trick the person who taught me to grow showed me, white vinegar will bring ph down, this was 40 years ago when u could not buy ph up down but be careful if you decide to try, plants finished up fine.