LaMotte Pool Manager Water Quality Handbook - Manual (Page 44)

Scale
Crusty white deposits on pool surfaces indicate a
severely high level of one or more water balance factors.
Scale deposits not only make pool surfaces rough, but
also reduce water circulation by building up within the
filter and plumbing system.
If scale deposits are readily noticeable on pool surfaces,
pH, calcium hardness, and total alkalinity must be tested
and adjusted immediately. One, if not all three, is much
too high and needs to be reduced. Reduce the pH and
alkalinity levels first, because reducing the calcium
hardness level is difficult.
If high hardness or total dissolved solids is causing the
scale, it is best to drain a portion of the pool water and
replace it with fresh make-up water low in hardness and
total dissolved solids.
42
Scale formation on pool walls