How often do you replace the ozonator in your spa?

How often do you replace the ozonator in your spa?
Replacing....?
4  40%
Every 4 year
3  30%
Every 3 year
2  20%
Every 2 year
1  10%
Every year
0  0%

Number of Voters  :  10
First Vote  :  Tuesday, 12 May 2009 22:12
Last Vote  :  Saturday, 04 September 2010 13:26