Dusk - well, there’s a simple test to make: draw 400ml of water from your service boiler. Measure the TDS. Then you’ll have some indication of what’s inside. When I measure they on the Elizabeth, I know there’s only sodium bicarbonate. So the TDS is of sodium bicarbonate only. When you use bottled water like that, you have calcium, magnesium, fluoride, potassium, etc, etc.
Now a thought:
2L of Ashbeck : 60p - 40L of Ashbeck: £12.00
1 ZeroWater filter, which can produce 40L of pure water if your water is very hard: £19.99. If your water is moderate hard, it will be able to produce more. The jug costs £29.99, and includes 1 filter, so the jug as such costs £10. 200g of sodium bicarbonate which will last you a life time and allow you to pass on to future generations: £1.50.
You can get cheaper deals with the ZeroWater filter if you buy packs of 5. Same if you buy Ashbeck in 5L bottles or packs.
So it’s not so complicated after all. A ZeroWater jug will take the same space as two 2L bottles of Ashbeck.
Advantages are that you’ll know what’s inside your coffee machine, avoid scaling and worries, and save on plastic wastege.
Food for thought.