what do you think of my tap water...

the results are what the customer can expect. also the source of water I get at home is actually from the near by Arve river and not the lake.

 

And a barge or boat crashes or dumps fuel in the river without your knowledge and you kill your tank.

Tap water changes, it can change shift to shift at a treatment plant as chemical dosages and treatment techniques vary, or a storm blows through and water conditions worsen, or the pH changes when they add more alum for treatment or ???

RO/DI is stable and the same every time you make it with a properly maintained system. For the amount of money you invest in a reef, a RO/DI system is a literal drop in the bucket as far as expense. Remember, water is the single largest ingredient in a reef system and everything depends on its quality and its stability. Why not provide the very best? It should not even be questioned in my mind. I spent thousands of $$ on lighting, the very best live rock and sand, fish and corals, why would I skimp on water and have to worry if its sufficient or not? Makes no sense to me.