Operating instructions

Glossary
52
Total Alkalinity -
The ability of the pool water to resist changes in pH. The "buffering" capacity of the water. Additions of
Sodium Bicarbonate will increase the levels, expressed in ppm. Additions of Sodium Bisulfate decrease Alkalinity
levels. Acceptable measurements range from 80 – 120.
Total Dissolved Solids (TDS) -
is a measurement of the total amount of minerals, residue, and other particles that cannot be oxidized
from the water and remain. When water evaporates, dissolved salts, minerals, etc. are left behind. These
levels of dissolved solids increase in the spa as water evaporates over time. Tubs that have a high TDS level
means that the water is over saturated and cannot receive any more chemicals. TDS should never be higher
than 3000ppm. The water needs to be drained at this point, and the tub cleaned and refilled.
Water Hardness -
A characteristic of natural water due to the presence of dissolved calcium and magnesium; water hardness
is responsible for most scale formations. Hardness is usually expressed in parts per million. The ideal range
for Water Hardness is 100-250ppm, though 250-400 is acceptable. Soft water in spa will cause instant foaming
and staining of water and shell. Water with low Hardness is highly corrosive, causing significant damage to
any metal. Water will dissolve other minerals rapidly until it gets to saturation point. Large, coarse soft-water
scale will form as a result. Hardness levels can be brought up by using Liquid Calcium. Water that has hardness
is too high, can cause excessive scale formation. Water may also become cloudy or slightly discolored Hardness
levels can only be reduced by using an in-home water treatment system or removing water from the tub, and
adding distilled water.
Weir -
The device in a skimmer that controls the amount of water coming into the skimmer, and keeps debris inside,
otherwise known as a "flapper-gate".
Winterizing -
The procedure of preparing spas for freezing weather, in cold climates when the spa will not be operated. May
include draining and cleaning the shell, and opening connections to release water from plumbing and heaters.
Most people continue to heat and operate their spas in winter; for them, winterizing is not necessary if
appropriate measures are taken to prevent freeze-up.
Notes