Originally Posted by cherryblu
The water I have available is well water. Not a city line, so my readings are all I have to go by.
I suppose my only concern with my pH is when I purchase my new fish at the store, their water's pH is about 7.0 exactly or 7.2. I know about letting the bag sit in your tank from the temperature to equal but transitioning from a 7.2 pH to a 6.4 could be detrimental... so how do I cure that problem?
I have an even greater variance. I let my tanks lower naturally, I only "buffer" pH in 2 of the 7. The 5 naturally fall to pH 5-6, perhaps lower, no test kit reads below 5. I have all soft water fish, mostly wild caught from similar water. The stores here tend to buffer their water as they have such a mix of fish, so they will be anywhere from 6.5 to 7.2 depending upon the store.
When I get the fish home, I float the bag to even temp, then add some tank water to the bag, leave for 15-20 minutes, then add more; about a cup each time. I usually do this twice, maybe 3 times with especially delicate fish. Then I net the fish from the bag into the tank.
I know of some professional aquarists who never mess with the water mix, they just equalize temp and then in go the fish. One of these is an importer of fish, and his fish are very healthy, and those I have acquired from him have not been problematic.
It is true that pH and hardness changes can shock fish, and we should avoid creating them un-naturally in an aquarium. But the degree to which most fish can adjust is likely greater than we might expect. The pH in a planted aquarium fluctuates every 24 hours, from lowering during darkness and rising during daylight; this is caused by the depletion (during the light) and replacement (during darkness) of CO2 which affects the carbonic acid in the water. The daily fluctuation can be .4 or .5, and fish manage fine with this. Something very similar occurs in nature. It is slower obviously, but the point is that the fish do cope with it.