you just have to test it, trial and error...i've had a few times where i've added enough ammonia to raise the level to 8, and i don't think it really had any effect other than my not having to add any more for a few days.
also, i would use a small liquid measure, with mLs, and start at 1 mL and work your way up until you see how a mL corresponds with ammonia levels. just pouring from the bottle isn't too precise (ahem....note comment about a level of 8, haha).
also, be SURE your ammonia only includes ammonia hydroxide, no surfacants. this is a mistake i made....its not fun to have to tear the tank down and clean and start all over again, so check your ammonia before you start :)
Edit: and yes, heated water will make a HUGE difference, as BlueHaven mentioned. my tank's almost finished its cycled (2nd attempt) after about a week because i have the temp up at 83*.
Last edited by celine18; 10-25-2010 at 06:57 PM.