Thank you so much for your response. Unfortunately, I didn't measure the Hydrogen peroxide I used but I poured liberally. I used a drug store brand of Hydrogen peroxide. The bottle doesn't specify that it is 6% concentration, but I hope it will suffice. I did shift through the gravel at least 7 times over the past couple days and I noticed loads of small bubbles in the solution mixture and on the gravel.
I poured out the solution an hour ago (at 4am!). I had the gravel in a huge bucket out in the yard, so hopefully none of the neighbors saw me out on the street dumping out water and shifting/scrubbing through the gravel with my hands. If the neighbors saw me, they probably think I'm some crazy insomniac with a pebble obsession -- shifting for gold on the street~!
I rinsed the gravel about 25 times with fresh water and laid the gravel out to dry. It's suppose to be a cold day so hopefully the gravel will dry out fine. I plan on soaking the gravel in boiling water once the gravel dries. I have to get rid of this algae for good this time.
Ergh, I really would prefer to not sacrifice any creatures, especially not my beloved neon tetras. I actually spent three hours picking out the ramshorn and Malaysian trumpet snails before I even started the solution soak. I tried to save as many snails as I could, but I know I couldn't save them all. These poor creatures -- they suffer because their negligent owner somehow got their home infested with this nasty algae.
Thank you for all your best wishes and for your gracious assistance. I hope I will be triumphant as you. You are super awesome!
Hopefully everything works out. A million thanks and have a wonderful day.