I had put my 20 gallon filter on my 10-gallon, it was running there for about 9 days to get my 20-gallon cycled quicker. Just today I filled the 20-gallon, added Prime and put the filter back. I added 5 drops of clear ammonia and the reading was only 0.50 ppm. I hope I am using the right ammonia. ..the ingredients are ammonia hydroxide and surfactant. Is this the right type to use?