Cycling a Fresh Water tank

Question
Hi There
I was wondering how can you tell your aquarium has finished its first cycle?  My ammonium is at 0 (after being at 8), nitrites are at 5 and nitrates are at 40.  I have been cycling for 4 weeks.
Thanks
Todd

Answer
Hi Todd,
Thank you for your letter. If you follow the easy care holistic instructions at my site, you will put your mind at ease. Please read and print out for future reference:
http://steamboats.com/aquarium.html
I suggest adding a little Cycle (friendly bacteria product) to your tank, even though you have let it cycle for four weeks.
Nori