i use an old mag float as an algae clip.
btw, as long as you make sure a good amount of food makes it to the bottom, you should not have a lot of dead nassarius.
as for increasing the CUC as the bio load increases, you need to remove nutrients from the tank. it's a sealed system. you can't get things that eat waste to help, because they just crap it out as well. you have to completely (manually) remove it. you can run an algae free tank without a single snail or crab. i've done it.