the quality of the products you use to adjust ph will have a large effect at your overall ph's integrity as far as fluctuation and buffer itself. No, it's not neccasary, but i reccomend using ph products designed for use in hydroponic systems. Really if possible, use products that are formulated for the specifics of the cannabis plant. I'm just saying that using hot tub ph down is comparable to waking up and eating a bowl of dogfood. Its not harmful to our overall health and wellness but adversly effects our quality of life. Treat your ladies with love and care and just like anything else you will see the fruits of you work quite literally.