No Ammonia spike!

[mrhasan]

Hello everyone,

It's been almost a week since I am running my new 20L saltwater tank with live rock and aragonite sand (regular not the live one) along with a CB false percula (the sale tempted me to buy it ) and a brittle star.

The following are the parameters my tank is maintaining for the past week:
1. pH: higher than 8 but lower than 8.2, probably 8.1
2. Ammonia: 0ppm
3. Nitrate: 0ppm
4. Nitrite: 0ppm
5. SG: 1.024

I am using 20lbs of initially cured live rock and the rock has already started getting diatoms. I have heard that diatom bloom only occurs at the end of cycle but I have not seen any spike in ammonia or nitrite and my fish is, I can say, VERY HAPPY because it even eats from my hand, responds to my movement and was talking a nap under the filter outlet!

Can anyone suggest what is going on?