Tetra Aqua products?

It is pretty instant i tend to put some drops in then stir it with the end of my algae scr or my net then i just siphon it back into the tank. It doesnt matter too much as long as you get it really mixed in there as you will still have dechlorinater in from your last change which will aid the process. If your from england Wilkinsons do a great weekly cleaner which removes ammonia and nitrates. i pop a cap full of that in with the aqua safe and its a good mix. Also if you have the means try half distilled half tapwater and see if that works my nitrates are a little on the high side but my ammonia and nitrite is 0 from when i first started out they were much higher.