Windows service allocates memory continuosly, how can I handle it?

Question

I have created a windows service that starts a thread which writes periodically to a database.
It is doing the job that I wanted but there is a problem.
In the task manager the process that starts by teh service increases in memory usage, 8 KB every 30 seconds.
Since the service is ment to be ran 24 hours a day. I think that the memory usage increasing is a problem.
Does anybody know how to handle this?
Thanks in advance.