Hi, you are already doing one of the things I would advise…you are here! Researching, learning, and asking questions helps a lot. It can keep mistakes at bay and help you to make good decisions that won’t lead to poor outcomes.
My second piece of advice is to make any changes slowly. Fast changes may help with the initial problem but could cause new issues to arise. A mature reef tank has a certain balance and if you tip it too fast in one direction you derail that balance.
My third piece of advice is the welfare of the creatures you are caring for should be of top concern. Make sure you are housing them in the appropriate environment for that creature, be it size of tank, tank mates, type of food, etc. Respect their needs.
Lastly, enjoy the mini ocean that you have created. It’s a big accomplishment especially at your age!