You are sure that it is only dead algae, right? A filter will not eliminate live algae.

But before replacing your filter, put a cup or two of DE in the sand filter and see if that doesn't clear up the water. Some algae is smaller than what a sand filter can remove so sometimes it needs a little help.

Given that you close your pool for the winter and I assume that you have a green mess at opening, a cartridge may not be your best choice. Sand filters are perhaps the easiest filters to have during opening.