YES! The algae grows hog wild in an area as small as the filter. If you can
find a light-weight piece of flat rock (like slate or similar), use that. Or
maybe a piece of plexi-glass (I painted mine with fleck-stone and put plants
on it!). You can make a 1 x 2" frame with slats that will fit over the lid,
and you can put plants on that, too. But do something to cover it to keep
the sun out as much as possible.

Lee

"Szpond" wrote in message
...
The
lack of light WILL hinder the growth of algae, which is *good*.

Lee,
My biofilter is wide open, should I put a cover over it. Would this help
with
my algae problem? Thanks, Cathy