Long weekend feeder options for salt water?

[fishoholic]

I have an 8g bio-cube set up at my work, The bissell centre. There is 1 clownfish, 1 green clown goby, 1 hectars goby a peppermint shrimp and a cuc. We are closed for 4 days over the long weekend. I do not have the code for the alarm (I will be asking for it, so I can go in and feed the fish) but I'm not sure if I'm allowed to have it.

I know there are those white cubes of food for fresh water fish to pick at if your gone away for awhile but I don't know if there is anything like that for saltwater fish. The repashy food (the uneaten portion) rots after 2 days so that won't work and since it's a bio-cube I can't think of a spot I could put a fish food timer on. Any ideas?