Amazon 500ml Kleen off Ammonia
Many members have used this household ammonia successfully for fishless cycles, its basically ammonia hydroxide (ammonia & water only), at 9.5% strength.
Amazon Dr Tim's Ammonium Chloride
Again, members have used Dr Tim's ammonium chloride with success, though the dosages may differ from the Kleen Off ammoina, so you do need to read and follow the bottle label carefully.
eBay concentrated aquarium ammonia
This is what I have used in the past with no problems at all, though you only need tiny dosage amounts of this ammonia since its highly concentrated at 35% ammonia strength so do be careful with dosages, a 1ml syringe is ideal for measuring accurate dosages btw.
(do note seller is not processing orders for these at the moment, until 23rd Jan 2017, but you can put on watchlist or something if you're patient)
Basically what you are looking for is any ammonia product that only has water mixed with ammonia (ammonia hydroxide), pure ammonia is far too strong and certainly not recommended, strength usually at 9.5% for most household cleaners.
Make sure there is NO added chemicals of any kind.
A small tip, if you shake the bottle and lots of bubbles/froth occurs then don't use, if only a small amount of bubbles/froth and dissipates quickly then that should be fine to use. And lastly, don't smell too strongly of whichever ammonia bottle you get, its pretty heady stuff and can cause nausea etc.
Hope that helps in your quest
