That's the thing, I am not. I flood once a day and early flower even skip days between watering. The RW cubes just hold so much water and I use small 4x4x2" on top of it. What contributes to cube algae in my case, is the fact that light gets through all the way, because the plants are lollipoped for SOG. Gives nice ripe buds on the entire plant, but also lights up the cube and algae grows.
I have experimented with cube covers, but have not come to a conclusion as to what is worse: algae on cube or a worse breathing cube as it is covered up.