High tech light, low tech tank question

[dustbust_1]

I have a 1 gal cube with amazon sword and some other petco plant I cant identify. Growth is decent. Slow but healthy. I have 2 cherry shrimp in there and 3 blueberry shrimp coming.

I dont dose ferts though Im going to start
no CO2
No Filtration just weekly 25% water changes and natural plant filtration
lighting, 1 3w CREE DIY LED full blast (HAS A DIMMER) Photoperiod 8hrs
pure sand bottom

Plants grow slow which im ok with since this is a office tank and I want it low maintenance. Shrimp are dark red and healthy.

But I get a lot of algae on the acrylic walls of the tank im constantly scrubbing. None on the plants.

any advice on how to fix this problem. Like is my CREE too bright for a non CO2?

Thanks folks