Stains on the leafs of the coconut palm

[Ilovepalm]

Hi. In May, I bought a nice healthy coconut palm. I look after her in such a way, that she is in a palm pot with an adapted substrate mixture. At the bottom of the pot there is expanded clay and burned holes. I have a temperature of 27-30 Celsius in my room. Every day coconut is sprinkled with warm water or a humidifier is used. I water about once a week either on the saucer or alternately from the top. Twice a week I put him in a steamy bathroom for a few hours. Despite this, ugly spots appeared on the leaves of the palm tree. I don't know if it's a mushroom? I must admit, that I recently had a massive spider mite attack. Now, it is calm for now. I live in Poland, so there are generally no tropical conditions here.

I Please, help me.

This is a gallery of these leaves:

https://postimg.cc/gallery/w3SL7vQ

This is what the palm looked like right after the purchase. This is a palm tree on the right. I got my second palm from someone to save. The purchased palm tree gave birth its new leaves.

Edited July 14, 2022 by Ilovepalm

[Ilovepalm]

Is there anyone here?

[floridaPalmMan]

The only thing I know of that discolored my coconut was the fact that an AC duct was blowing conditioned air right over one of the leaves and that dried it out.

As soon as I changed the direction of the air duct, new discoloration stopped appearing.

Thats my best guess but this is my first coconut palm and have yet to raise one from seed to maturity 

[Ilovepalm]

@floridaPalmMan thanks, but I don,t have air duck at my home.

Edited July 16, 2022 by Ilovepalm