Do/Don’t use the starter?
Its a "if it does not benefit, it will not harm" concept...
In general, it is not needed to boost bacterial development in the filter or substrate. They will come and develop on their own devices, the needed bacteria are omnipresent. The bacteria also live in large numbers in symbiosis with plants in and on the roots, thus adding plants already seeds the substrate sufficiently with bacteria. It usually takes several weeks to grow into a healthy population. In general consensus, about 6 weeks will be sufficient.
How long it takes before it is safe to add life stock to your aquarium depends on several factors. The biggest concerns in this are Nitrite and Ammonia buildup and release into the water column. Both are severely toxic to water life and should be avoided or if present waited out till its no longer present. It depends on the substrate used, some substrates are pre fertilized or contain organics that initially will leach Ammonia into the water column. Then regular water changes and regular testing is required to determine when the substrate stabilises and is done leaching nasties.
Then it's water change, test, water change, test and so on for a number of weeks till you are clear from Ammonia and nitrite in the water column. This can take longer than 6 weeks.
In the case of an inert substrate, there is nothing present to leach into the water column, then much fewer water changes are required. And the aquarium could be ready to populate a tad sooner.
Next to this, it also depends on the type of life stock added and the bioload that comes with it. Shrimps, for example, have a rather low bioload on the system. But a number of hungry fish that require a lot of food and after this poop a lot have a much higher bioload. Uneaten food and poop is an extra organic load that requires a fully developed bacteria population to clean it up. If this is not the case then this organic load will rot and turn into Nitrite and Ammonia.
Best practise is be very patient and plant your tank up, wait for all the plants to establish and grow sufficient healthy new foliage.
This can take up to a few months. Because sufficient healthy plants are key and much more important for a stable system then the bacteria are. Are you less patient and would like it sooner, take the above into account with the use of some common sense.
