Mama- you are not working in ammonia-n etc. You are still using your API kits. If you want to translate his numbers, use the chart I posted earlier.
NH3 and NH4 have slightly different weights due to the the extra H in NH4.
N= 14.007
H = 1.0079
NH3 = 17 and NH4 = 18 and that accounts for the difference. It is also why NH3 is more toxic. It is smaller and can fit where NH4 can't and that gets it inside the fish. the odd part is once inside it turns into NH4 because blood pH is higher inside the fish.
You will often find the ammonia conversion stated as 1.3 - supposedly rounded up from 1.28. In fact the exact weight would be a combination of the weights of NH3 present in the test and then the NH4. But the reality is it is never above a small number. I use the 1.28.
The key to understanding the API type test kits results is to look at the atomic weighs of all of it all, Nitrite is NO2
N= 14.007
O= 15.999
NO2 = 14.007 + 31.998 = 46.005
NO3 = 14.007 + 47.997 = 62.004
Note, there is one N at each stage- that lets scientists add up the nitrogen and ignore the rest. So they use the N scale and the scale of N is constant from start to finish.
The test kits we use count in the other stuff which means there is a magnification of the ppms each step.
1 ppm of ammonia becomes 46 /17.9 times as much nitrite or 2.6 times and that becomes 62/17.9 or 3.5 times.
3 ppm of ammonia becomes 7.8 ppm nitrite and 10.5 ppm of nitrate.
I have folks do two additions of 3 ppm.:
6 ppm of ammonia becomes 15.6 ppm of nitrite and 21 ppm of nitrate.
But the fact is the nitrite will start to turn into nitrate along the way and that will prevent the nitrite from getting up to that theoretical maximum. And by the time the 1/3 maint. addition goes in, nitrite is falling sharply and the addition wont really slow down that side of the cycle by much at all.
The numbers mean the amounts given in the directions and the time to do things are designed to make it impossible for the nitrite to reach the danger level on an API kit of 16.5 ppm of nitrite. Further, they are designed to prevent the accumulation of ammonia similarly. 5 ppm ammonia-n = 6.5 ppm on the test kit I have only 6 added in two spaced additions. The only problems hat might come in relation to low pH, KH and/or O.
However, there was only so much to put into the article, I mention these three things but that is all. I still need no to write a testing article to try and explain all of the above clearly. But also to show when and where kit results can go wrong and why. There is a reason for those pesky .25 ppm ammonia readings that are really not there. There is a reason nitrate kits can be unreliable, especially during a cycle when nitrite is present as well.
One of my hopes in doing some of these article was to create a place to send folks to read when those same old Qs come up. I would rather see the OP told to read here, then come back with your Qs than have a bunch of people all trying to explain parts and sometimes wrongly so. On average i read about 5-20 abstracts and peruse several full research papers on related topics every week and have now for a few years. And I am still a rank amateur. But I know a lot more than I used to and have disabused myself of a lot of urban aquarium myths along the way. I just want to share that with folks because the info will help one be a better informed fish keeper I believe and hope.
One last note mama- Dr T's directions may be a tad confusing. On day two you test and add the half dose. His directions will not let you overdose doing that. It doesn't matter what numbers you test at. If you start at one drop/gal you hit 3 ppm ammonia-n (2ppm + 1 ppm), if you start at 1.5 drops you hit 4.5 ppm (3 ppm + 1.5 ppm). Both are under the 5 ppm-n danger line. Remember, he works in the -nitrogen (-n) scale. so just do the day two 1/2 dose w/o question