Regardless of what corals you get, you shouldn’t base your tank’s readiness on the growth of coralline. If you’re going to keep corals, and especially stony corals (LPS and SPS), you need to be testing your water regularly (at least until you get enough experience to be able to look at your tank and have an idea of where your parameters are). You need to be able to troubleshoot and ensure that your parameters are stable. It’s just part of the care requirements for keeping these animals.
The only other advice I can give you (without specific questions) is to go slow, start with soft corals, and make sure that you research the corals you want before you bring them home. We see a lot of people new to the hobby post pictures here asking what the coral they just bought is, if the LFS recommends a specific coral, ask what it is and don’t be scared to do research there at the store if need be. We often see new people get sold corals that are not appropriate for beginners or for their specific tank set up, unfortunately there are a lot of LFS’s that are more interested in making a sale than helping you choose the coral that is right for you/your tank. When selecting corals, only buy corals that look clean, are open and have fully extended polyps, that don’t have exposed skeleton (again, wait to buy stony corals until you have more experience), and lastly, don’t buy an anemone until you have some experience with corals.
All that said, corals really aren’t as difficult as people make them seem. So long as you provide appropriate conditions, can monitor your parameters, and go slow, you’ll have a thriving reef in no time (but again, go slow, lol).
Edit: you will likely need to upgrade your light, there are plenty of options and it can be confusing, so if you’d like recommendations, feel free to ask.
