Water Testing and Changes

Every time I test my water the Nitrate is 0 ppm, why could that be happening? I have read that usually it should read around 20 ppm.
My tank is a 5 gallon fluval with plants, one betta, and some snails. I use the API master test kit

 

How long has the tank been set up? How often do you do water changes? Is it heavily planted? How is and has been your ammonia and nitrite?

 

That usually means it isn't cycled unless your plants are eating it up. Or if you recently performed a large water change that could be it.

 

How long has the tank been set up? How often do you do water changes? Is it heavily planted? How is and has been your ammonia and nitrite?

It has been set up sense January 18th, there are 2 sword plants, one Anubius and frogbit
The Ammonia is always 0 and the nitrite is always 0
I change 20 to 25 % of the water every 5 days

 

I don't think it's cycled.

 

It has been set up sense January 18th, there are 2 sword plants, one Anubius and frogbit
The Ammonia is always 0 and the nitrite is always 0
I change 20 to 25 % of the water every 5 days

I think that you are just changing your water frequently enough that you are removing the nitrates. Just don't ever clean out your entire filter as that could lead to an ammonia spike because you removed all of the beneficial bacteria. Keep up the water changes and it should stay at 0 or very very slowly climb. If you stopped the frequent water changes I think it would rise over time to the nitrate level you were expecting.