I need to raise my skimmer about 3 inches and have been looking at making a pvc stand. My question is if I still holes in the pvc is that in turn going to make the inside of the stand a diatoms factory due to the little to no waterflow?
So I shouldn't cap the legs? As far as the egg crate goes that is reef safe correct? Was going to use that as a base for skimmer. I remember years ago there was thought that the egg crate caused hair algea?
Eggcrate (white) light diffuser does not cause (depending on your definition I suppose) algae to grow. It does provide an exellent place to grow algae. It's white and reflects a lot of light back ensuring good lighting for algae. It's shape and slightly rough edges give algae a great place to grab on and take "root" and it makes it annoyingly difficult to clean should small amounts of algae start to take hold.
So while it doesn't "cause" algae it absoutely provides an exellent place for algeal to thrive.
It is highly unlikely that a 6 inch piece is holding up a skimmer is going to become an algae farm because there is unlikely lighting pointed at the skimmer.