Ecoskim Comparision with a Standard Skimmer Box

The graph below indicates how Ecoskim saves water by substantially reducing the amount of pool fill ups required.  It uses actual rain statistics form Brisbane Airport.

The period used (Nov. 2005 – Oct 2006) was a period with substantially lower than average rainfall occurring.  As shown, the ordinary skimmer needed 10 fill ups and the Ecoskim fitted pool only required 1 – if it was attached to a downpipe diverter or tank it would have required no fill ups. 

Our trial pool located in Chermside has not had a town water fill up since Ecoskim was installed 18 months ago, for the past 6 months the pool has been attached to a downpipe diverter.

The trendlines on the attached graph are based on rain and evaporation statistics at Brisbane Airport.(Nov 2005 – Oct 2006). This graph is based on mathematical extrapolations of this data and is not representative of an actual Ecoskim trial pool.

Explanation of Graphical Data

Trend Lines:

The pink trend line represents a pool with Ecoskim retrofitted. This trend line does not include the decreased evaporation rates caused by a drop in water level. *  
The blue trend line represents a pool with a standard skimmer box and no other water saving devices.

Vertical Axis:

The figures on the vertical axis represents the level of water where 0 is the ideal operational water level of the standard skimmer box (approximately the middle upper portion of the box). The pool coping is the equivalent of +100mm.

Horizontal Axis:

Accumulative days of the year where Day 1 equals 1 November 2005 and day 365 represents the 31 October 2006

Pool Top-Ups:

When the blue trend line reaches – 35mm the standard skimmer box will become ineffective. It is assumed that the pool will then be filled up by 35mm, which is the equivalent of 1400 litres of town water in an average size pool. When the trend line goes over 35mm water it is assumed the water will either overflow or have to be pumped out of the pool for the skimmer box to work effectively.
On the chart the standard pool is filled up 10 times. The pool water has overflowed 3 times which equals 5,264 litres.
With an Ecoskim fitted the pool does not need to be filled up until 350mm under the coping. In the chart this is equivalent to -250mm on the vertical axis. For easy comparison we have also made this a 35mm top-up of 1,400 litres. On the chart below this occurs only once.

It is also worth noting that Brisbane Airport received 54.8mm of rainfall in the first 17 days of November 2006 – the beginning of the rainy season in Brisbane.

Use of Ecoskim with other water saving devices

If Ecoskim is used with any or all of the following water saving devices - pool blanket, tank or down-pipe diverter - it will greatly increase its effectiveness at saving water, even in areas where less rainfall occurs. In South East Queensland average rainfall would ordinarily compensate for average pool evaporation with the stand-alone use of the Ecoskim device.

Qualifications of the chart data:

1. Evaporation – evaporation data used in this model is a derivative of Pan evaporation (Highest possible level of evaporation). This was compared to evaporation data from Department of Natural Resources (actual evaporation of pools) to develop a ratio that more clearly represents the evaporation that would occur in an average pool. These figures show slightly higher evaporation than those observed in the Ecoskim trial pool. Actual average evaporation levels are very hard to quantify due to differing weather, exposure to elements, pool water temperature, surface area, colour of the pool etc. One of the most evaporative elements in this equation is exposure to wind. *
2. The evaporation figures used in this chart are conservative estimates. In realty it is expected that the Ecoskim will provide even better water saving results (as observations of our trial pool indicate). 

* The evaporative effects of the wind on a pool surface are reduced as the water level decreases. Therefore in an Ecoskim pool evaporation rates will be reduced markedly from the graphs theoretical representation when the water drops from lack of rain.(on average winter or off-swimming season in S.E.Q)