A lot depends on where the spring is--so go online and check out the specs on any spring water company you are thinking of using. I had to switch to spring water last year when the tap water become too lethal for aquatics even after using dechloramining chems. Once you start using one brand, stick with that brand since all springs are not the same, and if you decide to change brands, do it gradually so the fish can adjust to the new water composition. You should not have to dechlorinate bottled spring water (but read the label & website specs). Spring water will be expensive and getting that much water for every cleaning is going to be a pain but for some of us, it's worth it although we might not keep as many fish anymore as we'd like to. NOTE: distilled water is water that has been put through the reverse osmosis (RO) system (evaporation and reconsitution) and does not contain the minerals aquatics need to remain healthy--your fish won't immediately die (probably) but like malnutrition, they'll eventually get sick and die so it is not advisable to use distilled water. "Drinking" water or purified water is merely tap water (someone's tap water) that's been put through purification and filtering (and maybe chemicals) to take out or neutralize enough bad stuff to get the water certified as drinkable for humans by whatever water agency oversees such stuff--it doesn't necessarily mean the water in the bottle is ok for fish (so you'll have to read the label, get a more detailed listing from the company, to see if you need to dechlorinate).