When comparing quality to quantity in terms of water types:

1. pH Levels: An 8.5 pH alkaline water typically has a higher pH than standard spring or purified water, which usually has a neutral pH around 7. Alkaline water is believed to help neutralize acid in the body, though scientific evidence supporting these health claims is mixed.

2. Purity and Composition: Alkaline water often contains minerals like calcium, magnesium, and potassium, which can contribute to its claimed health benefits. Spring or purified water can vary based on source and treatment processes but generally lacks added minerals unless they are naturally present.

3. Plastic Bottles vs. Cans: Alkaline water in cans can be advantageous over plastic bottles because it avoids potential chemical leaching from plastic, such as BPA or phthalates. Cans are also more recyclable and environmentally friendly compared to plastic. Studies have shown that nano-particles of plastic have been found in human bodies, specifically in men's testicles, which may be linked to various health issues and complications. This raises concerns about long-term exposure to plastic contaminants from bottled water.

In summary, quality refers to the mineral content and potential health benefits of the water, while quantity pertains to the volume of water consumed. For overall health, the quality of water (including pH and mineral content) can be more significant, but staying hydrated with any clean water is crucial.