I guess maybe coralline algae is sucking it up? I'm not too sure. Green hair algae doesn't mean you failed, that's a totally normal part of a new tank. Especially if you start with live rock. What I would suggest for hair algae is snails and a yellow tang maybe some hermits and an emerald crab but only after the tank is cycled and reading 0ppm ammonia. I just fear that the LFS took advantage of you because you're new. A lot of people don't run half the filtration media that you are running and still have very successful tanks. Another way to remove green hair is just to pull it off rocks by hand as often as you can. It's a lot of work but it's more natural than all that filter media. The main issue with starting a tank off with all that fancy stuff is the tank will begin to rely on it. And that's a lot of stuff that could eventually fail and cause another ugly algae outbreak. It's all preference though, I just prefer to use less because it's cheaper and it all works out in the end. Hair algae isn't harmful for anything unless it's smothering corals which you don't have yet I'm assuming? So just take it slow and steady! I hope to hear you succeed this 3rd time around and no offense but definitely quit asking the LFS about anything [emoji23] they just like to sell you stuff lol.