In the last few days, my alkalinity consumption has increased drastically. At the same time, my calcium does not budge, it stays within the range of 440-460ppm. I am using a saturated NaHCO3 solution to manage my alkalinity. My issue is that in the past, I would use 5mLs of this solution and the alkalinty would raise by 0.3. Now I might add 20mLs and it won't even raise by 0.15. My pH is around 8.15-8.3. The solution still is saturated since there is undissolved NaHCO3 at the bottom of the bottle. The weather is also hotter right now so the concentration of dissolved NaHCO3 should be higher. What could be causing this? I also have Ca(OH)2 at home, but I am not looking of raising Ca2+ in the water, that's why I am using the soda. There is no visible CaCO3 precipitation at the place of the dosage. What should I do?