How long have you had the plants in there for? If it has been added recently it’s normal for plants to melt at first. Do you have carbon in the filter? That can take out the fertilizer. Do you have enough light for the plants? What lights are there?
I think my Amazon sword is showing #3!
I'm using flourish root tabs. How would I supplement manganese for swords?
I found 32% Mn powder. Can I dose in the water column? What percent should I dose?
B. Terminal bud remaining alive. Symptoms on new growth.
1. Interveinal chlorosis on young leaves.
b. Interveinal chlorosis with smallest veins remaining green producing a checkered or finely netted effect. Grey or tan necrotic spots usually develop in chlorotic areas; the dead spots of tissue may drop out of the leaf giving a ragged appearance. Poor color. Potassium excess can inhibit uptake of manganese... manganese deficiency
I downloaded your picture, cropped, enhanced, and added some arrows so you can see what I see.
View attachment 424704
The two #1 arrows point to new leaves coming out stunted and with a 'downward hook' at the leaf tip........calcium deficiency.
The #2 arrow is pointing at a leaf that is showing interveinal chlorosis (dark green veins with lighter leaf material in-between). If this is an older leaf it indicates a magnesium deficiency; if it is a newer leaf it indicates an iron deficiency....is it a new or older leaf?
#3 arrow is the winner of the group! I do not believe I have seen a better example of a manganese (not magnesium) deficiency; notice the fine 'netting' effect of the smaller veins with the lighter interveinal material? Manganese (not magnesium) deficiency
Please let me know if the #2 arrow is pointing to a new or older leaf....if it is a newer leaf then if you know your pH please include that with your response.
Actually sounds like I really need a GH booster? Are those always safe for fish? I have some corys. They don’t do well with salt I thought. Would Epsom salt have the same affect?
Epsom Salt (magnesium sulfate) is not "salt" in the same sense as sodium chloride (regular rock/aquarium salt). I keep several species of corydoras in my tanks from the more common C. aeneus to the less common C. sterbaI and have had no issues with using GH Boosters or Epsom Salt; in fact they breed regularly.
For Arrow #2 I said you likely had either an Iron (Fe) or a magnesium (Mg) deficiency depending upon if it was a new or older leaf....I do not believe you responded. I said there was a manganese deficiency indicated at Arrow #3.....they are not the same.