Looks like a lot is going on in that tank. Could you give us the details abut the tank itself and any water parameters you've tested for?
Moreover, I would start with a large water change 50% at least. I would manually remove as much of that algae by hand or with a siphon before the water change. Then I would clean every piece of equipment you have, including that canister filter, and the glass. Give the sand bed a decent vacuum as well if you can.
I would then start a regiment of 20% water changes every few days to help export nutrients.
You could also run a black out period(no lights) for a few days to help reduce the algae.
Are you using tap water or RO/DI water?
Also is that a zip tie on that powerhead? And if so, why is it there?