System Sizing for Spas
System Sizing
Use these three formulas to calculate the volume of water in the spa:
Rectangular:
Length(M) x Width(M) x Average Depth(M) x1000 = Total Litres
Length(Ft) x Width(Ft) x Average Depth(Ft) x7.5 = Total U.S. Gallons
Round:
3.14 x Radius (M) x Radius (M) x Average Depth (M) x 1000 = Total Litres
3.14 x Radius (Ft) x Radius (Ft) x Average Depth (Ft) x 7.5 = Total U.S. Gallons
Free Form:
Average Length (M) x Average Width (M) x Average Depth (M) x 1000 = Total Litres
Average Length (Ft) x Average Width (Ft) x Average Depth (Ft) x 7.5 = Total U.S. Gal.
IMPORTANT CONCEPTS
1 . Sanitizer Demand
The rate at which sanitizer is consumed in any spa depends on the relationship of eight major variables.
Since these variables can vary widely from spa to spa and season to season, precise prediction of the
sanitizer
demand
for
any one spa is difficult. At the end of this section, rules of thumb are provided for the
EcoClean System Sizing.
THE VARIABLES ARE:
1. Volume and surface area of the spa being sanitized.
2.
Average water temperature maintained: As the temperature of the water increases, the sanitizer
demand
will
also increase. As the temperature of the water decreases, the sanitizer
demand will
also
decrease. When this happens, the output dial should
be decreased to compensate for this lower
demand
(which will also protect your equipment from excessive levels of sanitizers).
3. Cyanuric acid level
maintained: This chemical, when added to your outdoor spa water, significantly
inhibits sanitizer depletion from exposure to sunlight. Cyanuric acid also inhibits corrosion if your spa is
equipped with any metal components. Minimum levels or better must be maintained to ensure that the
sanitizer being produced is protected from UV breakdown.
4. Bather load: As the bather load increases, the sanitizer
demand
will also increase.
5.
Amount of direct sunlight / UV exposure: Spas exposed to larger amounts of direct sunlight are more
vulnerable to increased sanitizer loss and algae growth. Indoor or screened spas have less sanitizer
demand.
6.
Exposure to vegetation and airborne debris: Dense landscaping near the spa, along with increased nitrate
levels (urine, bird droppings, fertilizer, well water, etc.) greatly contribute to increased sanitizer demand.
7.
Chemical dilution: Virtually all spa chemicals experience dilution through rainfall, adding of fresh
make-up water due to evaporation, splash-out, filter backwashing, leaks, etc. When freshwater is
added, sanitizer
demand
increases for a brief period.
8.
Main filter pump runtime and your spa's circulation patterns: Waterfalls/Fountains and other water
features operated by the filter pump can directly effect sanitizer
demand.
The main filter pump runtime
and/or output dial may need to be increased to satisfy this higher
demand.
COAST SPAS EcoClean Production Capacity
3
Section 1 a