Doesn't hurt but it is Not Necessary !
I'm on well water, ppm of 450-500 depending on the season, ph of 7.5
No ph down, Mega Crop one part, towards the end of flowering 7.5g/ 4L, ~ 1000 ppm.
3 gallon fabric pots, 600w MH/HPS in a 4' x 4'.
Sativa Photo's, 50 days of veg. A total of 120...