I use 26 ppm water for my DWC system. No nutes, no additives, nothing. pH is around 7.2.
I lower the pH to 5.8-6.0 using Terra Aquatica pH down, and after like 3-4 hours, pH goes back to 7.0.
I again add pH down and reach 5.8 pH, wait another 4-5 hours and it is still the same. I repeated at...