Yes you need to test for Ammonia,Nitrate and Nitrite...but not yet.
It will be Ammonia 0 because you have nothing in there to create Ammonia (ie: fish waste,food waste)
This is what i do when i first cycle tanks:
Set the tank up,dont bother with decholrinator on the initial fill as you have no bacteria or fish or inverts to harm.
Leave it 24 hours to gas off naturally
Plonk in a prawn from the supermarket and leave it there for a week,it will cause a significant amount of Ammonia (it will go furry)
Take out the prawn then leave the tank for another week or 2 then test to see if the Ammonia/Nitrate/Nitrite has disappeared.
If there is some Ammonia left start your water changes,if there is not start stocking slow with a small fish.
PH 7.2 is perfect for a community tank,most fish are bred in that water and the only times i personally change the PH is if i am keeping Discus,Malawis or Marine.
If you want to keep Tetras and live bearers together then 7.2-7.5 is perfect.
People will start saying well 'Livebearers liek brackish' 'Tetras like acidic' but i can tell you first hand they are fine
