I'm thinking seriously about modifying my orchid humidity trays by setting egg-crate louvers such as are used in recessed lighting on top of the aluminum pans I have instead of using pea gravel. This would lessen the chance of algae build up and the louvers are easier to clean or so says my 'Orchids for Dummies' book. Does anyone know of a source for some metal ones? I looked at Lowe's and Home Depot but all they seem to show are the plastic ones and I don't know if they'd be strong enough. I guess I'd have to look at them to see first.

Not an expert here but I do think plastic would be plenty strong enough. I would cut them in pieces that would fit in the dishwasher so they could be sterilized every now and then.

Thanks Alice, I'll have to check them out down at Lowe's. I know the plastic ones would be less expensive than the metal ones. Probably if I space the pots out evenly it should work. As far as sterilizing them, I'm the dishwasher I have a large tub in one of the greenhouses that I use to sterilize my pots with a water and bleach mixture.