That stuff looks like the dreaded Black Beard/Brush Algae (BBA).
Algae in the Planted Aquarium-- Guitarfish
For most of us it's triggered with unstable CO2 delivery. And the red ones look like ones that have been squirted with excel and are dying. Red BBA is a most welcome sight as it usually means they're on their way out. There's been numerous threads about BBA on here if you search for them. It's one of the most vexing algae because for a lot of people, its hard to resolve. Many quick fixes exist and I'd love to tell you to just keep squirting excel on them, but unless you get to the root cause, they'll just come back.
The root cause for this and any other algae is usually .. too much light.
Perhaps a more detailed way of saying this is: too much light for the carbon that you're supplying. It seems like the only carbon source that you have is excel and even that is done irregularly.
One of my usual recommended readings for anyone new and even anyone who needs a reminder occasionally (like myself) is Darkblade's Primer to Planted Tanks
There's perhaps way more info in there than you need at the moment, but the main takeaway is this:
Grow healthy plants and algae won't happen. How do you grow healthy plants? You try to strike a nice balance of CO2/nutrients/light. As you peruse these forums, you'll notice people aligning themselves along with a low tech or a high tech approach. Either approach is still based on achieving that balance -- just at a different point. It may help to adopt this mindset (excerpt from aforementioned primer) "Think of light as a gas pedal of a car. The harder you press down on the gas pedal (the more light you have), the faster your car will go (the faster your plants will grow). However, the car will require more regular maintenance (your plants will require more maintenance, i.e. fertilizers, CO2, etc)."
Your out of balance area is probably that you're supplying too much light and not giving fertilizers (nutrients) and CO2. As you have low tech (read: low light) friendly plants, and if you don't feel like diving into the world of high tech tanks which require much more attention, you can just simply dial back that light period, add floaters, raise the light, add a screen, or any combination of all 4 and any ideas you have, to reduce the light received by your java ferns and wait. Your plant growth rate will slow, but the plants will be healthier for it. And along the way, the algae will simply stop showing up.