Im glad to know theyre recovering! Ive never used langbeinite but I dont see how it could hurt as long as you use the recommended dose. Nature's living soil is an all in one fertilizer though, I dont see why you would have deficiencies assuming the PH is right but I cant see their list of ingredients so who knows... If you have them written in the container could you please list them here? Maybe they couldnt take enough nutes cause they didnt have enough water. In any case, proceed with caution, its easier to overfertilize them than to starve them. I use several ammendments to make super soil and later on I use the same ammendments to top dress, but I also work with liquid organic fertilizers so I dont go too heavy on the ammendments. Ill leave you a list of organic ammendments that your microorganisms will love and what are they good for, starting with the one you wanna use:
1. Langbeinite: potassium magnessium sulfate (potassium, magnessium and sulfur)
2. Leonardite: humic and fulvic acids. They contain NK and a lot of micronutrients. Fulvic and humic acids help regulate the ph of the soil so its not alkaline nor acidic, acts as ph and nutrient buffer and contains important micronutrients (Every time I refeer to micro nutrients is mostly trace minerals like iron, silica, copper, zinc, manganese, etc)
3. Worm castings: Same use as leonardite because of the humic and fulvic acids it cointains. Difference? They do have nitrogen, as for the PK depends on the manufacturer, sometimes they have sometimes they dont. Your microorganisms like it more than leonardite too. Rich in micronutrients aswell.
4. Guano: this is tricky, there's bat guano, regular guano, seabird guano... and even the same types of guanos can contain very different ammounts of NPK. One thing is clear though, guano helps the roots during veg and makes tastier flowers during bloom. Thats attributed to his high phosphorus (and sometimes nitrogen aswell) contents.
5. Kelp meal: Low NPK but high in minerals, aminoacids and vitamins. Alginic acid is very good for plants and contains manitol, a form of suggar that is very good for your microbes and your plant metabolism. It also contains fitohormones: auxins (root hormones), cytokinins (growth hormones) and betaine (helps plants not get thirsty by protecting the cells from dehydration and promotes photosynthesis)
6. Alfalfa meal: mostly NPK and sulfur. Like Kelp meal it contains vitamines but it also contains
triacontanol.
Triacontanol is very good to enhance your plant metabolism, making photosyntesis better, promoting the production of proteins and enhancing nutrient transport through the plant.
7. Crab meal and krill meal: They will have different NPKs depending on the vendor but for me one of the most important things of crustacean meal is chitosan. Chitosan is found in expensive liquid nutrients like Bud Factor X from AN (sorry Mike, I know you wanna keep it secret, in your defense I will say that yours is cheaper than other brands) and they take it from crab or krill meal, which is inexpensive in comparison. Chitosan properties: promotes germination, promotes growth, helps inmune system, helps them manage stress, chelates heavy metals so your plants can absorb them and finally and most importantly for me, gives you better quality buds.
8. Azomite or volcanic ash: I think is common knowledge that the land surrounding volcanos is extremely fertile. Thats due to past eruptions. Volcanic ash is very rich in anything your plant wants, excelent source of micro nutrients. It doesnt contain nitrogen or phosphorus but you bet its gonna make your soil better.
9. Epsom salts: unlike all the ammendments I will mention, this one is water soluble which means that is fast release instead of slow release, treat carefully as too much magnessium is bad too. They contain around 10% magnessium and 13% sulfur, the rest os mostly oxygen (thats why they dilute so easily in water). They help clean your soil from accumulated salts and some peopel use it in the first watering when flushing because of that but is also good to use once a month or so and go for some runoff.
10. Dolomite lime: 30-35% calcium and 15-20% magnessium. Works very well to mantain a good PH aswell. If your runoff comes acidic, dolomite lime is gonna be your friend. If you already have too much calcium and magnessium then the next one will also help with ph issues.
11. Diatomaceous earth: commonly use to kill gnats, but they kill almost any insect, adults and larvae, mixed with the top layer of the soil. Its mostly silica, which helps your plant autoinmune system and also helps them grow thicker like calcium. Careful though! As the ph of
diatomaceous earth is around 8, great to solve acidity problems but if you dont have them and you use too much you can create nutrient lockout due to alkaline ph. 1 or 2 applications during all the grow should be fine though, I use it in almost every grow, either mixed with the soil or top dressed to kill gnats. Contrary to what some think, it doesnt kill your microorganisms, the micro crystals that form
diatomaceous earth stick to bugs and dehydrates them but your microorganisms are too small to get hurt by those crystals.
12. Bone meal: almost entirely calcium and some phosphorus.
13. Blood meal: High in nitrogen and a little bit of PK aswell.
14. Fish meal: High in nitrogen and phopshorus.
15. Phosphorick rock dust: self explanatory, lots of phosphorus and also lots of calcium. Silica is present too in relevant quantities. Contains other trace minerals aswell.
16. Tree ash: high in calcium and a decent ammount of potassium. Biggest taker from tree ash is probably the minerals it provides.
17. Palm tree ash: high in potassium and some phosphorus and magnessium. Like tree ash, its also rich in minerals. I use some to top dress in flower.