Other Homework Help

I have a newly set up and planted aquarium (29 gallons) under a high output T5 lamp. I recently came back from a three day vacation to find all of my plant leaves hosting a strange, stringy algae. I’ve checked pics and I’m pretty sure it’s not hair or beard algae, and it doesn’t seem to permanently stick to a single plant, because as soon as I detach a strand, it flows in the current and attaches to another plant or decoration. It is very fibrous and almost disintegrates in your hand, so I want to know what it is and how to get rid of it. I’ve heard of Seachem Flourish Excel, but I can’t personally buy it anywhere! I would also like to know how to get Excel, but not offline. Thanks! Here’s some pics of it.image.jpg