Hi everyone!  
I set up this aquarium around March and added the fish towards the end of April. I’ve always noticed that this kind of brown “dust” tends to settle, especially on the bottom of the tank. It often settles on the leaves of the plants as well, making it difficult for them to photosynthesise properly.  
Three weeks ago, I added one of my Blue Dream shrimp to the tank as an additional test, since they are more delicate. I’ve noticed that it has gradually become more and more transparent. This may or may not be related to the issue, as it could simply be due to moulting.  
Since I’m still quite new to the aquarium hobby, I wanted to ask if anyone has any advice on how to solve this problem.  
I have one of those lights that simulates a 24-hour day/night cycle, but I’ve now reduced the lighting period to six hours in an attempt to limit the spread of these algae.  
I’d really appreciate any advice, as I’m genuinely trying to do my best!

Here are my water parameters, which I have just tested: (with Sera quick test)  
No3 25   
No2 0   
Gh >14°d  
Kh 10°d   
Ph 8  
Cl2 0   
Ammonia 0

Thank you in advance to everyone who takes the time to reply!  
I know some of the values are high, but I can’t figure out how to lower them. I also did a water change this morning.

Ps. Inside there are 8 galaxy rasbora, 3kuhli loach and 2 sewellia for 40 liters tank

Something wrong with my thank?