I concur;)Most people keep rock and macro algae in their fuge. So the short answer is yes. The more nutrient export you have the better your parameters will be.
You may not notice the difference right away but it will help with nutrient export and water stability.So would a 3 gallon fuge make a noticeable difference on a 20G tank? I am not really looking to breed pods too much, more for maintaining better water.
Any sort of algae growing will help, it's not perfect, but it's better than a poke in the eye. I'm installing a 29 gallon under my 57 rimless this weekend with a 3" sand bed, caulerpa/ chaeto and a few pieces of rock to help starve out what little hair algae I have.Ok, so its actually 2.5G not 3 but regardless it will help keep my ammonia and nitrates down a decent amount? I do not expect it to magically make my water perfect or allow me to forgo water changes.