The fitting with solder have a ring shaped bulge about a cm from the opening. You will see silver coloured solder in a ring shape on the inside. You shouldn't use solder ring fittings as the metal in the solder reacts with the acidic wort
Yes, buy a salifert profi test kit for calcium. Costs less than a fiver and I assure you that the amount of calcium in your water will change from month to month. Definitely worth doing. You might consider getting a hardness/alkalinity test kit too. :thumb:
Im no expert on this tap, on my cooler I used a standard tank connector like in your second link and then used a standard hot/cold water isolation valve with a short length of copper pipe and an elbow to change direction of wort into the boiler. Order of connection. .. tank connector, home made...
Just pop a short length of pipe through the tank connector and tighten the compression fitting. I rarely remove this. The copper pipes within the mash tun just connect up to this pipe with standard non solder ring copper fittings (self feed).
On my setup I made a silicone washer cut from a non stick food grade baking sheet and didn't use the rubber one provided. I wasn't sure how 'safe' the material would be with acidic wort. This is on the inside of the cool box. Hope that helps?
You can get off smelling aromas during fermentation, if im worried I sanitise a spoon and taste the beer once fermentation has stopped. Some yeast is more prone to being whiffy than others. Did you follow the recommended temperature for the yeast?
Sorry to be so long in answering, had a bit of a non brewing stint! I have tried it and is still quite drinkable. Got away with it this time... luckily!
You can get keg 'spanners' that help you open them back up for a few £ and if you vaseline the o ring when you put the cap on, will come off easier. Don't know the diameter of the opening for the tap, sorry!