Okay, i have a theory. We both used aquasafe, we both have have to use alot of ammonia to get the reading to 5ppm, maybe it took so much because the aquasafe removed most of the ammonia and then left the correct amount of ammonia to get the water to have 5ppm ammonia. The aquasafe wouldnt be able now to remove any more ammonia, so we shouldnt need as much, i would say for both of us now to use an amount of drops worked out from chris cows experience, which for you would be 15 drops per day, as per his original recipe and i will use 18 drops (as i know my ammonia is only 1/3 as strong as his was)as per his revised recipe, which i can use as i know the strength of my ammonia.
It kind of playing on the safe side as his guide says that it is possible to put too much ammonia in, but too little would be better then too much.
Scott