which should i get if i can only get one?

ok so i've decided i really need to get my rear in gear and get my test kits in order. so i would like to know, which should i get first? pH, ammonia or nitrates? i'll be getting just the one this month and slowly build up. so which is more important?:blink1:

 

Ammonia would be best. Then Nitrates, then Ph IMO

 

I would say ammonia as this will kill fish faster in small amounts then the others.

 

ok, are there any good quality test kits out there that acurately test all 3? what about a pond kit? are they acurate enough for tanks? otherwise ammonia it is first, i think then i'd do pH as i want to try breed my corries, in particular my peppers and i want to find some more pandas so i'll definately need a pH kit to provide the correct conditions to get them to spawn. my lfs will buy whatever i can breed so i have a market for them and i have the tanks aswell to do it. hmmmm i hope my lfs hasnt got any new stock in as that = temptation lol