How much ammonia to add to verify cycle is complete

[DaveFe]

I'm thinking my cycle(ammonia portion at least) might be nearing completion but what's the true test to know? With my tank and sump I have probably 85ish gallons so how much ammonia should that be able to process in a 24 hour period, I know it's some PPM but I'm not sure how that relates to a real life measurement. So far I've just been putting some random amount of ammonia in and testing every day. The photos below represent 24, 48 and 72 hours after adding ammonia, I'm thinking the 72 hour is 0.

 

[Crabs McJones]

Add 2 parts per million ammonia and if after 24 hours you test 0 ammonia and 0 nitrites, you're cycle is complete. Also test your nitrate to make sure it isnt to high. If it is do a series of small water changes to bring it down before adding anything