Leaf spots (newbie)

classic signs of a Calcium (Ca) deficiency, likely compounded by a pH fluctuation.Septoria spots usually have a more circular yellow spots and darker centers. These spots look more like tissue death from the inside out. Test the pH and EC of the water coming out of the bottom of the pot to see if the medium has become too acidic or alkaline..once you know you can start to feed in the correct range. If you are growing with mineral salts then a flush may help to clear and reset the medium. If you are on organics I think it may do more damage than good. It's hard to know really from a picture of a dead leaf and no other real information . Good luck.

Before you rush into anything, check the undersides of the leaves for pests. If so, congratulations! If not, check if the soil is musty, rotten, or too wet (not just the surface). There might also be root rot. In that case, it's important to ensure good air circulation and allow a break from watering. If the lamps are far enough away, it can't be light burn. Unfortunately, it's not possible to tell much from just the two pictures. Otherwise, I agree with the previous comment: calcium deficiency and similar issues. 💚

On the available info which isn't much and no diary... It's 1 or all of these Septoria Leaf Spot: A common fungal pathogen that causes small, irregularly shaped spots with distinct yellow halos, which later turn brown and can lead to leaf drop. Calcium Deficiency: This can cause brown or bronze splotches or spots on the leaves, sometimes with yellowing. Potassium Deficiency: Symptoms often appear first on older leaves as chlorosis (yellowing), with leaf tips and margins turning a rusty color and burning. Rust Fungus: Another common fungal infection that leaves behind brown, rusty spots, often flourishing in high humidity and low airflow. pH Imbalance: Often, these symptoms are not an actual nutrient deficiency but a "pH lockout," where an incorrect pH balance in the soil prevents the plant from absorbing necessary nutrients.

I would say that is probably overfeeding. Provide some more photos from the plant to have a better look. Good luck!