Phil,
Your pH and other water quality questions are just a big enough set of topics that I know I won't be able to do them justice at this time, so I'll just make a small start, hopefully giving some big picture info that might help with later discussion. (Paul, I'm pretty sure Phil is well-cycled from his previous thread re it being an established tank with good stats that was acquired. But good to check on that as if it was a problem, all else would be less important!)
When it comes to the long-term pH of your tank, probably the most comfortable approach you can take is: "Your water is your water!" The water that comes out of your tap does indeed set the "complexion" of the type of freshwater tropical aquarium that will be easier to achieve, without going to great lengths and trouble. The first and most important rule for beginners to start learning is that stability of pH is more important than the actual pH. Fish that are able to stay in a relatively stable pH, only ever seeing slow changes will generally be better off. (Note that the underlying hardness of the water is intertwined with pH and is important to the osmotic systems of fish, but we'll ignore this for the moment in the interest of simplicity.) So... attempting to work against the tap water you've "been given" is considered by experienced aquarists to be "not something one undertakes lightly" and generally "not advised for beginners if it can be helped!"
When you "look up" writeups on individual species of fish, you will see a pH range listed for them. This serves as a starting point for learning about this aspect of what they like, but again, experienced fishkeepers will often obtain a more complex feel eventually about this for a given species. There are some species out there for whom its very important and others where it makes hardly a difference. Its also important to understand, as a beginner, that these pH numbers listed are often for wild-caught preferences and the fish we obtain in western society are often farm raised and quite used to whatever the local pH is in the LFS by the time we get them, so at first, its best to take the approach of not getting overly worried about this aspect of their environment. All this is just to say to take your time and work this out on a species by species basis with the members, if it seems it might be an issue. The fish I've seen you list so far are quite common and don't set off any alarms in this regard.
So back to the 8.0 to 8.5 you mentioned. This is actually fairly good in a number of ways, though you are correct that its on the higher side of the range. For one thing its the ideal growing pH for your nitrifying bacteria, which should always be a help in not having mini-spikes in ammonia and nitrite when you add fish and your filter is adjusting to the new higher fish load. For another, you may have a somewhat better environment for a wider range of live plants, which will be good. One thing you can think about that will be good would be the addition of significant amounts of bogwood decoration to the tank. This will tend to bring the pH downward a bit and is certainly a popular form of decoration.
You don't want to resort to any sorts of "pH adjust" chemicals, as these tend to make matters worse in the long run. And I doubt you'll want to fool around with filtered, bottled, distilled, "RO" or anything else that is not just tap water that's been treated with conditioner. All these can be discussed with the members, but they have real effects and should not be done by a beginner just thinking they are somehow good or are a solution to something.
~~waterdrop~~
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