If you can help me with some info and treatment for this. I have searched the internet and I am curious to see what you say.
It doesn't look like an algae to me. Probably your plants are having this problem because they are too close to the heater.
Do other plants have the same symptoms too? If they have, the problem is not that they are close to the heater. In this case, you should check your water parameters. Plants may not have received enough minerals... Maybe potassium or zinc?
The GH is around 100, I am using JBL clynol as a water treatment and for minerals. Other plants around the aquarium have te same problem
Maybe you should try add potassium. I don't think Clynol has enough potassium for plants.