Just curious to know whether you guys think bottled water is better than tap water. And if using bottled, what is an acceptable mg per litre amount for trace elements such as sodium, magnesium etc.
Are you growing soil or hydro?
The first thing to do is find out the ppm of your tap water. Measure it yourself, of if you're in the US, your water provider is required by federal law to provide an annual water quality report. These can usually be found at your city's web site. This will tell you alot about whether you need purified (reverse osmosis) water.
If it's over 300 ppm, you can mix rap and RO water to get 120-200ppm. My tap water is 700. I mix about 20-25% tap to 75-80% RO to get about 160ppm. I just eyeball it. I don't sweat it if it comes out 220.
You don't need to mess with aquarium tablets or aerating your water to remove chlorine/chloramine. Water supplies are closed systems which aren't expected to encounter bacterial load. They're not like swimming pools, etc. They contain a minimal amount of disinfectant to keep the pipes clean in this closed system. It doesn't take much bacteria to exhaust that amount of disinfectant. Put a pinch of sugar in the water to stimulate bacterial growth. Cough over your water. Or, just pour it into the soil. The first 1" of soil will exhaust the disinfectant.
Cannabis isn't complicated to grow. It doesn't need to be pampered. You don't need exotic bottles of nutrients. Some inexpensive Jack's Classic works fine and will save you a lot of money. (I use Grow More Sea Grow which is at the same price point. It produces great results for about $1 per plant, per grow.).
Regarding ph: If you're in soil ph of what you pour in doesn't mater much because the soil will pull the liquid's ph more than the liquid will pull the soil. Also, getting back to whether you use tap or pure water, using calmag to replace nutrients lost from filtration can cause you to use more ph-up. If you mix tap and filtered, you may find you don't need ph up (or, less reason to ph. There's not much reason anyway. But, calmag seems to be powerfully acidic. When I stopped using it my final ph was almost 1.0 higher.).