Progressive rusty spots on leaves

Hmmm, brown spots, most common nutrients thay cause brown spots are, Ca, Mg and K. Which also happen to be the big 3 soil cations. Bit other nutes can cause it too, the symptom of brown spots is generally causes by oxidative stress.........a symptom of oxidative stress, where an imbalance of reactive oxygen species (ROS) damages cells, leading to tissue damage and visible spots. This damage can occur due to various factors, including environmental stress, heavy metal toxicity, or pathogen infection....... If it was from excessive light it would be growth closest to source. Leads me think it's is nute based. Little to no tip damage, ec is good, transpiration is good if water flowing. Potassium Deficiency: A lack of potassium can cause brown spots on the edges or tips of leaves. (Responsible for tugor pressure) would be drooping too if deficienct) Calcium Deficiency: Calcium deficiency can lead to brown spots, especially on new growth, and can also cause leaf edges to curl or become misshapen.(old growth primarily) Magnesium Deficiency: Magnesium deficiency can cause yellowing between the veins, which can then turn brown.(possible but I don't see interveinal chlorosis) Nitrogen Deficiency: A lack of nitrogen can cause yellowing and brown spots, especially on older leaves.(possible bit not whay I'd expect, more yellowing needed, possibly early) Phosphorus Deficiency: Phosphorus deficiency can cause stunted growth and brown spots on leaves. Manganese Deficiency: Manganese deficiency can cause yellowing between the veins of young leaves, followed by dark brown spots. Boron Deficiency: Boron deficiency can cause leaves to appear small and crumpled, with brown spots, and can also cause sharp bends in the trunk. I'd be taking a peek at soil moisture levels too, leaning towards more environmental. Who knows, get a pH before anything that always helps. Would tell me little of whats going on in the soil how saturated you are in Ca , Mg and K these 3 are vitally important for soil composition and if they are all antagonists in that they compete with each other for cations if the ratio is way off for any 1 of the 3 it can jist replace uptake of all the others wreaking havoc with the soil possibly messing with moisture retention. People don't think of oxygen as a nutrient but it is, it's very weak bond means it easily reacts. It's a requirement in soil, in flower with the heavy canopy and increased carbon sequestration the soil in flower can become slightly wetter than one is used to. When roots are saturated, the soil becomes waterlogged, and oxygen cannot reach the roots, leading to anoxia (oxygen deficiency). Under anoxic conditions, plants produce reactive oxygen species (ROS), such as superoxide radicals (O2•-) and hydrogen peroxide (H2O2). This gets shot up the stems with water and burns the epidermis layer. It's not so much a deficiency as much as it is sucking up free radicals along with everything else. Antioxidants, like vitamins C and E, can help neutralize superoxide radicals and other ROS, preventing or minimizing the damage they cause. If worried about chlorine use 1mg of ascorbic acid in 5 gallon jug will instantly dechlorinate and de chloramine your water. Just make sure to not add too much as it very strong acidifier. Magnesium is a nutrient that is found as central atom in chloryphyll, although it presents as mobile nutrient within the plant. It's also constantly used and replenished throughout a plant's life, as the Magnesium is spread all over the plant it can take alot of the radicals with it all over the plant as it seeks to replenishing, basically anywhere water goes. The more water that has passed through a part of plant more damage its getting. Not so kuch mobility but a side effect of water transportation, nutrient distribution and cooling. Soil contains reactive nitrogen species (RNS) due to both natural processes like nitrogen fixation by bacteria and human activities such as fertilizer use and fossil fuel combustion, which increase the amount of nitrogen compounds in the environment. Reactive nitrogen species (RNS) are chemically reactive molecules containing nitrogen, like nitric oxide (NO) and its byproducts, that play diverse roles in biological systems, including signaling and defense against pathogens, but can also contribute to tissue damage. 🤔 Nitrogen toxicity is possible too and it fits but if that were case you probably would have noticed delay in flowering. Reactive nitrogen species (RNS), particularly nitric oxide (NO), can react with reactive oxygen species (ROS), like superoxide (O2-), to form reactive nitrogen-oxygen species (RNS/ROS), such as peroxynitrite, which can lead to oxidative stress and cellular damage. Gluck, hope she recovers strong, buds looking frosty.