You'll want to read:
http://www.fishlore.com/NitrogenCycle.htm for a good explanation of the nitrogen cycle. we have hard water and high pH here and the fish don't mind it, they're used to it and fish are happier with stable pH, kH, gH even if outside recommended zones than they are with those things going up & down on them. If you do want to soften water, do what luniyn recommended with peat moss or driftwood, but be sure you can find a good reputable source for it locally.
I'd really recommend the API master freshwater test kit. The test strips tend to be inaccurate and I just read yesterday where someone who liked to use strips tried the liquid testing and found his strips had been giving him very off results.
Angel fish are very territorial and you need to be careful what you put in the tank with them. Bettas and Tigers wouldn't be compatible and you'll end up with a lot of dead fish most likely. Plus more than 1 betta will result in them also fighting each other. Bettas have a short list of compatible fish including otos and corys. They're just very territorial, even more than the angels.