If you have an algae problem, and if it won't go away, and you may have had high PO4 levels and you have sand, it's then plausible that said sand is binding the suspected PO4 within it's porous structure AND therefore, removing and/or replacing said sand "could" alleviate or eliminate the original problem of algae in a tank.
That about it, Albert?
Gobies won't clean it, sifters won't sift it, chemicals may leach it back out, but a quick way to fix is to remove. As an option. If you wanted to fix it quickly. It may or may not appeal to your aesthetic sensibilities, but can and often does fix a particular problem.
Mental note, install breathalyser on Submit button
