I actually have some red algae in the tank itself. I am planning to add more algaes eventually.

Approximately how much algae per gallon do you guys use to help with filtration. For now, they will be in my tank...so something attractive (or that can easily be stuck behind the rocks) is what I am looking for.

At present, I have around 2 handfuls (but my hands are fairly small ^_^ ) in my 75 gallon. I had a codium plant, but it disintegrated! Not sure what happened there. My calcium levels have been good...