I had spirogyra not too long ago, man it's impossible to get rid of. I don't think upping your c02 helps at all, it just grows even faster. I tried peroxide and excel with no luck. It seemed to slow the growth but it would come right back. I put my fish into a qt tank and treated with algae fix. Why expose your fish if you don't have to, too many reviews of fish deaths. I treated for about a week to make sure it was gone, it worked. Riccia tied to rocks melted, but grew back after treatment ceased. All my other plants including mosses faired just fine. Spiro hasn't reared it's ugly head since, it's been about 3 months.