Water affects coffee preparation, but a single total-dissolved-solids reading does not describe every aspect of its chemistry. The source discusses mineral balance and encourages closer attention to the water used for brewing. Hardness and alkalinity are related measurements with different roles, rather than interchangeable names for purity.
Before changing a recipe, establish which water you actually use. Compare a small number of suitable drinking waters while keeping the coffee, dose and brewing method fixed. Record the product or treatment method so the comparison can be repeated. Avoid assuming that the most expensive bottled water must be the best match.
Equipment requirements also matter. Follow the machine manufacturer's water guidance and maintenance instructions, particularly where scale can affect operation. Do not mix mineral concentrates casually without a reliable formulation and accurate measurement. For a home brewer, a stable water source and a clear comparison often provide a more useful first step than chasing a complex mineral recipe without a baseline.
The conversation
A good question can make a better brew.