To the OP, there are many ways to speed a cycle. But they pretty much all involve starting with more bacteria and also staring with both types. When We use a proper bacterial cycling product it contains a matched amount of ammonia and nitrite oxidizers such that whatever the ammonia ones can convert into nitrite, there will be nitrite ones to consume that nitrite. Seeding bacteria removes the sequential development normally accosiated with cycling where, first the AOB colonize, and then the NOB follow once there is nitrite. Both types are present in the bottle (but not in Stability). The nitrifying bacteria do not form spores. So stability contains no autotrophic nitrifying bacteria at all.
It is a known fact that aquatic plant host nitrifying bacteria. So, when read what
Il_bristlenose_catfis wrote above I wonder how he determined how much bacteria there was on each of the plants in his tests. There could have simply been more nitrifyng bacteria one the plants that landed in the tank with Stability.
Next, temperature has an effect on the speed of cycling, how do you get the exact same temps in the two tank almost constantly? I am also curious as to the control method used to insure the amount of ammonia going into or being created in each tank was the same?
Fortunately, as a Psych major in college I dis some experimental psychology. So I have a bit of grounding in how the create an experiment. Anecdotal evidence is not science. I can give you hand if you really want to do thing "right."
Get three tanks of the same size with lids. Ideally, you should have replicates rather than a single tank for each test group and the control group.
Get pure water (ro/di or distilled).
Get three heaters and heater controllers.
Get three as close to identical filtration systems as possible.
Get Stability and also Dr. Tim's One and Only.
Get a remineralization mix to add back to the pure water.
You need a lot of measurement devices. There must be a similar amount of everything going into each tanks. Identical wold be ideal but, unless you have a lab, you will not have access to proper test equipment. But the more accurate measurment devices you can get, the better.
Now- set up each of the three tanks bare bottom with no decor or plants of any kind and not in sunlight as algae use some ot the same things as the bacteria.. Bring both tanks to temp. Then add equal doses of ammonia to produce the same ppm in each tanks. After you have confirmed that the 3 tanks are essentially identical, it is time to add the starter produce each to its own tank, There third tank is the control and gets no bacterial starter. Do not follow the directions for using the products as they are not the same. Dr/ Tin's needs a single addition to work, Stability requires multiple additions. These should not be needed it the product contained the right bacteria.
For Stability
Shake well before use. Turn off UV/ozone. Use 1 capful (5 mL) for each 40 L (10 US gallons) on the first day with a new aquarium. Then use 1 capful for each 80 L (20 US gallons) daily for 7 days. Fish and other aquatic species may be introduced at any time as long as dosage is maintained for 7 days.
For Dr. Tim's
Too long for here, use this link for the directions- note only a single addition of the bacteria is needed.
https://www.drtimsaquatics.com/resources/library/quick-guide-to-fishless-cycling-with-one-and-only/
Note, Dr. Tim states that when there is no substrate in a tank, the cycle will take longer. A lot of the bacteria ends up in the substrate but this variable can be eliminated with no ill effect on the experiement.
Test at least daily or more and record numbers as well as everything else you do. You need to report the Materials and Methods used and they must be pretty much identical for all three tanks except for the bacteria added. Because the three tanks are expected to cycle in different times, you will need in your methods a plan for when and how much ammonia gets added to each tank for the cycling. The one thing not to do is to use fish. These become an uncontrolled variable. What if one fish in a tank dies? How can you get the fish in each tank to make the same amount of ammonia?
Remember the goal is to determine which tank cycles the fastest. I know which one I wold put my money on. Another important part of the experimental design is no live plants as they make the experiment worthless. The same would apply to using fish as the ammonia producers. Lastly, be sure to control the pH in all 3 tanks. Changes in this greatly effects the speed at which the nitrifiers reproduce.
You are not able to do some of the tests needed for the above to rise to the level of being science. You have no way to test for exactly what bacteria are in the three tanks.
As for those who feel they understand how the ammonia bacteria can survive when they lack ammonia or oxygen etc., have a read here. They discuss recovery times after starvation.
Joke Geets and others, Strategies of aerobic ammonia-oxidizing bacteria for coping with nutrient and oxygen fluctuations,
FEMS Microbiology Ecology, Volume 58, Issue 1, October 2006, Pages 1–13,
https://doi.org/10.1111/j.1574-6941.2006.00170.x
Full paper here:
https://academic.oup.com/femsec/article/58/1/1/468326?view=extract