Get the CO2 going asap.
Then add lots of plant sand then light.
You can run a fishless cycle if you want without any plants or lighht for 3 weeks prior, or.............not bother at all with FC and simply add the plants and luight and CO2 and nutrients from day one, you can also use some dirt from a local friend's or LFS's filter to seed the filter, add a few fish each week rather than all at once, keep good plant growth going etc, you will never need any cycling at all.
Another simple way around the need for cycling and adding toxic pollutants:
User zeolite and activated carbon when you start up a new filter, by the time the media is spent, the tank is abotu 3-4 weeks old and the bacteria are alrerady cycled.
Yet another method and one many Discus keepers and many others wisely use: a weekly 50% water change, sometimes more frequent/larger in the start up phase till things get going and then back down to 50% weekly etc.
All these methods conspire to eliminate the need for FC.
You did not need it before, and you do not need it now.
You also have no need no matter what you believe to add it(NH3) to a tank.
Simply cycle the filter in bucket and add NH3 to the bucket and wait 3 weeks etc, then add the filter to the tank, never add NH3 to a tank.
This keeps the NH3 out of the tank and reduces the need for any testing.
Makes me wonder about folk's sanity when they read the FC baloney, they did not think that one through very well when it was sugegsted and many jumped on the bandwagon. Newbies fall prey to that stuff.
Mulm, the dirt in the gravel or filter of a well established tank is the idea culture to add and most are verty willing to offer it for free or if you have a tank already, adding this to the filter and to the substrate adds precisely what is missing from a new tank's filter/substrate.
Bacteria and organic matter that they live on and are eating.
It does not get any better than adding the specific microbes you need from a live culture thriving.
Water changes, chemical media, good stocking routines, lots of well growing plants, moderate light, good CO2, mulm etc all make FC uneeded.
I've yet to have any issues with cycling after setting up hundreds of tanks over three decades, working at LFS's etc, never found a need for the FC and knowing a bit about the cycle myself, I find it incredulous of folks to carry on when I criticize the method agressively as it should be.
NH4 production of waste is from only one significant source in the tank: fish.
Thus if you add NH4 removing media, live cultured bacteria from an estbalished tank, do routine frequent water changes(you should do this anyway), stocking fish slowly rather than all at once, add lots of plants that have a good place to grow well(plants alone without good conditions makes for a worst place otherwise-> rotting plants!), simple things that reduce the need for testing, practice good mainteance for aquariums, by the time the media expires, the bacteria are there anyway.
There are plenty of better methods that suit all aquarist, not just planted tanks.