Entirely new here but have a low-to-medium light setup. What types and where from do you all get your dry ferts?
At the very least, you will need
a trace mix (CSM+B, Iron EDTA, etc)
You can also supplement with things such as calcium sulfate, magnesium sulfate and potassium sulfate, depending on your water parameters.
I got my dry fertilizers at a hydroponics store; I believe some users also sell them on these forums (I would as well, but I am in Canada, and shipping across the border is a hassle).