Looking closely at the hard spotty stuff, you'll see that some is green (GSA), and some is black (beginnings of BBA or black cyano), mixed together and sometimes overlapping.
Plus I just barely see some fuzz algae on the sides of some leaves. And there may be some GDA on the hardscape, or just really heavy GSA; you can tell the GDA apart if some is soft and will rub off.
Blends like this means there's plant health issues, and maybe insufficient turnover and conversion of organic wastes, due to something limiting plant growth. Could be insufficient light, low CO2, low nutrients, insufficient flow. Look at the algae distribution. Is it mostly at the bottom of the tank? Then check flow and light, which both have a more difficult time reaching the bottom.
If you can post or link tank parameters, we'll look them over.
The algae is worse on plants that are low growing. I had some low growing plants but they just got covered with the black algae. The driftwood I know blocks alot of light and that is why I have decided not to have any low growing plants right now. At one time when I didn't have the driftwood and had alot of stems, my tank flourished like this...
Maybe I need to get rid of the driftwood and go back to stems.
Tank : 90 gal Corner Bowfront
Lighting: Coralife Compact Flourescent (4) 65watt 6700K/10,000K bulbs + a Fishneedit T5 (4) bulb fixture (1 socket doesn't work so really only 3 bulbs). I just changed out these bulbs about 3 weeks ago because it had been over 2 years since I last changed them (No $)
Water: RO/DI water and was using Equilibrium at water changes but will begin using GLA Ultimate GH Booster. I was trying to do 50% water changes every week but just starting trying a new method to try and save money because money is tight.....I want to continue to do EI dosing but spreading it out over a 2 week period to where water changes are done every 2 weeks, so instead of dosing let's say 1/2tsp of Potassium Nitrate on Mon., Wed., & Fri. I will dose 1/4tsp on Mon., Wed., Fri., Sun., Tues., Thurs. and then WC on Sat.
Filtration: (2) Fluval 404's but in process of adding a Fluval 304 and possible another. It is very difficult to get the correct flow in a corner aquarium plus I am becoming more convinced everyday that good flow solves alot of problems.
CO2: Pressurized with one line going to a Rex style reactor and the other line going to a glass diffuser.
Dosing: Modified EI Method. Dosing CSM+B (1/8tsp, T,Th,S,M,W&F), Iron (1/16tsp T,Th,S,M,W&F, Potassium Nitrate (1/4tsp M,W,F,SU,T,TH), Potassium Sulfate (1/8tsp M,W,F,SU,T,TH), Mono-Potassium Sulfate (1/2tsp M,W,F,SU,T,TH)
Pic of tank so you can see where my returns are located