Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
While it is true that ammonia in a low pH tank is mostly in the ammonium form this is not always true, and I would always play it 'better safe than sorry' and not add fish to a tank with any ammonia showing, no matter what the pH is.
Nitrite is toxic. It crosses the gills to enter the blood and makes the blood not carry oxygen very well. In an established tank with an emergency going on you can do water changes to keep it low and add salt (sodium chloride) to reduce the amount of nitrite that cross the gills. But in this case, a new set up, it is not an emergency. Simply do not add fish. The nitrifying bacteria has not grown to the proper level.
If the plants are gobbling all the ammonia then you should not be seeing nitrite or nitrate. Nothing remains of the ammonia to get turned into nitrite or nitrate.
Since you are seeing all three, the plants are not removing all the ammonia, and the nitrifying bacteria are growing, but not enough yet.
Continue monitoring and doing water changes. The optimum for nitrifying bacteria is to keep the ammonia and nitrite under 5 ppm. The nitrate level does not matter.
Some plants do not like high ammonia, and would prefer the level not go over 1 ppm.
Continue planting as your plants arrive.
Ultimately your tests will show the ammonia is staying lower, perhaps hitting zero. The soil is producing significantly less ammonia, and the plants and bacteria are dealing with that level of ammonia. Nitrite still show. Maybe you want to think about feeding the bacteria some ammonia or some fish food (decomposes to become ammonia and other things) to finish out the bacteria cycle.
When both the ammonia and the nitrite are consistently zero there are enough bacteria and plants to add fish.