Hi all,
There are a lot of parameters, the legal requirement is to put in values for pesticides (24 D, Aldrin etc.) and heavy metals (antimony, arsenic etc.). The law is very tight on these now, so I'm going to ignore them. Some other values we might be interested in, like Potassium (K) or Phosphorus (P), aren't relevant to human health, so aren't quoted.
The ones of most interest to us are these, I've given the average value, but the maximum values could be useful as well:
Ammonia/ium - <0.0215 mg NH4/l
Calcium - 36.8 mg Ca/l (mg/l = ppm)
Residual chlorine - 0.30 mg/l
Conductivity - 306 uS/cm at 20oC
Total hardness - 46 mg Ca/l
Magnesium - 5.61 mg Mg/l
Nitrate - 8.95 mg NO3/l
Nitrite - <0.0066 mg NO2/l
Hydrogen ion (pH) 7.32 pH
Sodium - 22.9 mg Na/l
The conclusion you can draw from these is that the water is definitely OK, it has small amount of ammonium, chlorine and nitrite, suggesting that you use a conditioner like "Prime", or an HMA filter. The hardness and TDS (conductivity x 0.64 = TDS) are middling, not really soft low hardness water, but not hard either. There is a bit of magnesium (useful if you grow plants) and quite a lot of sodium (not so useful). Nitrate levels are also fairly low.
You would really want the water a bit softer and with lower TDS for the more sensitive fish, so I definitely wouldn't use the pH buffer. Ideally you could mix the HMA treated tap-water with RO to give a TDS of about 100 - 150. Mac won't agree but another option is to cut it with rain-water (like Doug suggests). I've always used rain-water without any problem, but I'm lucky to live in a rural area, with little industry to the West or SW of me.
cheers Darrel