Thanks and I get your 20L surface area idea. I just still cannot comprehend why I get the algae I do with them plant mass I have. I'm assuming I just need way more stem plants.
I stopped adding ferts as a test because when I tried adding MORE ferts I'd get even more alage (definitely green spot from the phosphate and quicker green dust reappearance after cleaning).
The best the tank has ever looked algae-wise was right after christmas when I had the light and co2 set to an hour a day when I was on vacation. No more algae on leaves or on the glass. However the rotala wasnt as red and shrunk a little. I put it back up to 5 hours at 60 par and this happens.
So, I'm not going to discount any of the previous advice as they are all important and far be it for me to be able to add anything beyond what you've read on advancedplantedtank already, but in my little corner of a tank, I feel your issue might be similar to what I went through a couple years back. Let's also analyze what you said too. 1 hour of light, no algae; 5 hours, algae. Well, clearly the plants are running out of something when you push them for 5 hours. @1 hour, the plant is getting all the nutrients/co2 it wants so, probably no algae. This is a sign that you should keep your feeding your plants and trying to figure out what they're missing. A red plant needs to be healthy first, before it rewards you with its scarlet blush. Well, great, you think, my "healthy" settling point is 1 hour, but that's not enough to redden the plant. Not only that, it's not enough VIEWING time. How I am I supposed to enjoy my tank? Red plants are such an enigma sometimes. Well, here's where I feel that:
It's not only the amount of light, but equally important, the timing.
I've read that par is roughly equal whether it's 5 hours of 60par or 3 hours of 100 par, but tell that to the lower leaves that's not getting the expected par due to uneven dropoff. As a fellow current satellite plus pro user, I can attest that there's a decent amount of dropoff from par based on the placement of the plant. There's only 1 row of lights! So, your red plant might be wanting the 60par at the base, but because its placed in the back, it's probably only getting eh, 30 at the base? If you shade it with another plant -- even less!
What does it mean? It means you're not giving enough light for 5 hours for a plant to get red, but you're definitely giving more than enough for the algae to get rampant.
How to get around this? What you need is a midday spike. As you're getting algae at 5 hours, try, say, 1 or 2 hours of 60par and the remaining period of eh, 20par just for your viewing pleasure. In so doing, you're sort of simulating only 1 hours of lighting while still being able to enjoy your tank. OK, let's say I sold you on the idea, how to do this with a current satellite plus pro? Well, the default programming is a bust as it has no ability to do that, so you may either have to make one of those custom controllers that send the IR codes to do it or you get a second unit or some other light and put it on a separate timer.
It sounds like I said two conflicting things just now. I suppose it sort of is. You're addressing two issues. Less light to cut algae, more light to push for reds. First, you have to get the plants healthy. That means cleaning and figuring out the feeding regimen and proper co2 distribution, etc. Getting the algae to stop growing. Then, when you have green healthy (mostly) algae free situations, you can start toying with increasing the spike intensity to trigger the reddening, and so on. You may find that you do need a second fixture after all to help with the light intensity and spread in the later stages.
Finally, I suppose there's also a cheat to get that amazing bunch of crimson stems. This ties into maintenance. As a stem plant grows, even in the best scenario, the bottoms will start looking ratty or lose their color. In such a case, you simply have to uproot, cut the bottoms, and replant the best looking section -- the top. Do this a few times, and if you have a tank that is conducive enough for the plant to not lose their bottom leaves by the time the tops need a trim again, you'll get a whole stem that's pretty good looking.