Cycling and fertiliser

[fatbobsufc]

I began cycling my 44 gallon 10 days ago, but only added my fish (2 Platies) 4 days ago. My readings are currently as follows:

ph 8~8.5

Ammonia 0

Nitrite 0.3

Nitrate 5

My substrate is 3 inches of silica sand and underneath I have laid some Aquarium fertiliser. Could the fertiliser be affecting the nitrate readings? If not, then my cycling process seems to be advancing quite quickly.

 

[Alien Anna]

How warm is your tank? If you have the temperature fairly high it is entirely possible you already have nitrates, or they could come from the fertiliser although most aquarium fertiliser excludes nitrates.

 

[fatbobsufc]

How warm is your tank?

It's at 79 degrees