Explore Optometry. Home / Education / Admissions / Explore Optometry. A Doctor of Optometry (OD) is an independent, primary health care provider who examines the visual system, the eye and associated structures, as well as diagnoses, treats and manages related diseases and disorders. Optometry involves much more than prescribing and fitting glasses and contact lenses.
In most of the UK, when hard water is softened with water softener, the softened water is likely to comply with the Drinking Water Regulations, assuming that the concentration of sodium does not exceed 200 mg/l, it would be regarded as wholesome and therefore considered safe to drink over the long term.n most of the UK, when hard water is softened with water softener, the softened water is likely to comply with the Drinking Water Regulations, assuming that the concentration of sodium does not exceed 200 mg/l, it would be regarded as wholesome and therefore considered safe to drink over the long term.
If you have high levels of iron or manganese in your fill water, you should probably use softened water to fill your spa. With softened water it is important to use special test strips that measure total hardness in addition to pH and total alkalinity to insure the water is properly balanced when the spa is refilled.