If your soil was properly buffered than ph'ing the water is not neccesary. HOWEVER..... I've found that my soil plants have zero issues when I give the roots a little bit more room
Once a plant gets root bound in soil, you will most definitely see a lot of issues because the soil has lost it's ability to buffer. Trust me on this
A bit late now unfortunately but just wanted to give you a heads up for next time
It's really easy to see things and assume deficiency, but that just leads to chasing your tail and making matters much worse imo
I ammend my soil now so water only throughout the grow, but back in the day when I used basic soil with nutes I never flowered in anything less than 7 gallons and this fixed my issues buddy
 If you grow autos or don't veg for long at all than 5 gallon should be "ok" though. Still not optimal imo
So long story short, I'd buy a soil ph kit if I were you, test it to see where it's at, and we can go from there
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