While this product is typically for resovoirs, it has worked wonders for my microgrow. I store around 15 gallons of aerated, carbon filtered water at a time. My tap water is ph of 7.8 and ppm of 110-180. I use this solution at ~1ml/gal to drop the ph to 6.4. The ph of the stored water will remain stable for weeks (months?) with very little drift. While I check the ph frequently (I'm particular) I rarely if ever bother adjusting ph anymore. Nothing short of miraculous.
If you add too much solution dropping the ph below 6.4, you can simply aerate the water to bring the ph back up! If you're on the fence, I hope you consider this review. I'm speaking solely as a satisfied customer. I can't express how much time and frustration this product has saved me. Now I just water and wait