I had to use baking soda recently, and almost shit when i checked the fert PPM afterwards. My normal fert at full strength reads about 100 PPM, and after I added enough baking soda to bring the PH up to 6.5,(1 1/2 tbs per gallon) the PPM reading was almost 1,100! Holy fuck! I don't know if all that extra shit is salt or what it is, but i sure as hell don't want it in my soil. With the PH Up, it only added another 30 PPM, which is waaaay more acceptable to me.