Your light is your main culprit, plain and simple. Why mess with monkeying around with c02 levels and ferts when these things become more manageable by simply reducing lighting. Monkeying around wiht c02 levels and hitting on proper ferts(E.I) is your only other option, but given that most of your plants would not be harmed by 2 watts per gallon why bother doing things the hardway. When you reduce lighting IME and based on my testing, algae has a much more difficult time getting a foothold, you don't have to be as dead on with c02, worry about increasing them to levels that could harm your fish. The same applies for ferts as lower light will automatically slow down plant growth and nutrient uptake by plants will automatically be reduced giving you more wiggle room to get away with dosing less ferts. It doesn't need to be more complicated than it really is. I know what you are going through as I am on the tail end of trying to rectify similar issues in a 10 gallon, DIY c02, 30 watt tank after 6 months of no algae, no problems with water parameters. You can read about this here: http://azdhan.googlepages.com/thelostworld
After throwing everything at the tank but the kithchen sink, the solution(s) turned out to be quite simple and it is something I should have done a lot sooner to keep things from becoming as imbalanced as they did.
(1) "Immediately" reduced lighting to 20 watts from 30 watts and manually removed as much algae as possible. I suggest you do the same. Don't make the mistake I did of waiting before things spin too out of control to do this.
(2) Dosed 20 CC Seachem Excel daily and 20 CC excel with every water change. I used a syringe and you can get a pack of syringes without a prescription from your pharmacy.
(3) Do at least 50% weekly water changes and only rinse your filter media in tank water, do not replace any media for at least a month.
(4) get yourself 5 amano shrimp. They are industrious algae cleaners IME and will keep the tank free of dead plant debris that siphoning may miss that could contribute to algae growth.
(5) get yourself a mini hagen submersible filter and modify it as per directions in this thread to ensure Maxium C02 diffusion efficiency with the DIY.
For the record, I am not suggesting that you cannot set up a 10 gallon algae free tank with 3 watts or more per gallon of lighting. It can be done and has been, but your chances of success are more likely using ADA Aquasoil as a substrate. I have tried with lesser substrates(fluorite, and schultz aquatic soil) with no success. As evidence, here is Wood's 10 gallon tank with DIY c02, 46+ watts lighting, minimum water column fertilization. Try replicating his results without ADA Aquasoil and tell me what happens?
https://www.plantedtank.net/forums/ph...t-rebirth.html 3 months of neglect is what finally did that tank in. Further proof that you really have to be on top of things if you choose the high light route