Feed as much as your fish will eat in 2 - 3 minutes, making sure everything gets eaten. Like you are doing - spot feeding. It is a standard reply in the hobby, "You need to feed less." That's another "bad advise" I'd like the hobby to address. Every time I read one of those posts I think, poor fish are being starved to death.
My tanks get fed two times, sometimes three times, a day.
I should also address your issue of excess algae. You do need to address your nutrient export problem as evidenced by the quick growth on algae on your glass. Stepped water changes, dosing with vinegar or vodka, kalkwasser, bio pellets, stepped up skimming, or GFO to lower your phosphates.