First, just know there isn't a fast fix for getting algae under control. To properly manage, you'll want to balance this equation: nutrient import < nutrient export.
Right now your tank has a higher level of nutrient (phosphates, nitrates) source than you get rid of.
So you first want to look at how often and how much you feed as this introduces nutrients. Secondly and more importantly is keeping uneaten food and general waste from accumilating in the tank.
Easiest way is by siphoning during your water change. You'll want to siphon your subtrate (if it isn't very fine sand) or at least stir it up some to release any trapped waste. I use a turkey baster to blow the crud off my rocks once a week so that my skimmer has chance to collect it.
From your picture, I don't see a skimmer. So you may want to add either polyfill( doll stuffing) or other filter media to your hob filter and then stirup your tank sand. Create a mini storm if you must. Let the filter catch as much gunk as it can. Then do your water change and toss the filter pad. Scrub off as much cyano and algae during this time as well. Let the filter run for an hour or two with the media before doing your change.
If your sand and LR have excess bound nutrients, it will take some time for the rock to purge the excess and/or the algae to use what's left. By preventing new food/poo turning into more nutrients, once the current supply is gone the algae will receed as there is no food.
This is where you want to pay attention to how much food you feed and increase flow within your tank so waste doesn't really settle on the bottom. Skimmers are good at helping to pull this crud from the water when circulated, but if you don't have a skimmer (and generally a tank your size doesn't NEED one), the above routine will help prevent much of the waste from breaking down into algae food source.
This is why I say it takes time, because you are balancing the source of the problem. Phosban and other chemicals are good for attacking the symptoms, but getting to the source is the sure fire way.