I agree this thread only applies to fishkeepers on a municipal water supply, where chlorine, or chloramine is added, and would agree that for most fishkeepers following manufacturer recommended dosages is the right thing to do. Any info a fishkeeper not on a municipal source gives would not be relevant.
Because different water sources require varying types of treatment, those manufacture recommended dosages are a probably fool proof way to go.
If your water source is a river, water conditions are constantly changing, and so will treatment options at the plant, so trying to second guess or try to micromanage what your dose might could be troublesome
Because I tested my tank and tap water fanatically, almost daily, and had access to all the best available technology to run my tests I could make my own call on proper dosage. My water supply was also very stable (Lake Michigan) and treatment dosages did not vary significantly from week to week at the plant, sometimes even month to month.
Because different water sources require varying types of treatment, those manufacture recommended dosages are a probably fool proof way to go.
If your water source is a river, water conditions are constantly changing, and so will treatment options at the plant, so trying to second guess or try to micromanage what your dose might could be troublesome
Because I tested my tank and tap water fanatically, almost daily, and had access to all the best available technology to run my tests I could make my own call on proper dosage. My water supply was also very stable (Lake Michigan) and treatment dosages did not vary significantly from week to week at the plant, sometimes even month to month.