The maintenance required on your marine aquarium will depend on the type of setup and equipment you have, so it is impossible to have a standardised schedule of maintenance for all tanks. Keeping a maintenance log book will help to work out a schedule for your particular tank, and is also a good place to keep records of water test results. If you list all the items that require maintenance in your book, you can see when they were last done and ensure that no items are missed or forgotten. Maintenance should never be a major job and it is best to do everything in small, regular amounts. Getting into a routine will soon make maintaining your tank an easy and enjoyable task.
Whilst by no means complete, the list below outlines some basic tasks and how often they should be done.

Daily
Fish count – check all your fish are present and healthy
Feeding
Check main filter pump is running
Check temperature
Check protein skimmer cup for cleaning

Weekly:
Check all pumps are running correctly
Clear glass of algae & stir substrate
Water tests
Small water change & top-up

Fortnightly:
Siphon debris from substrate using a gravel cleaner
Filter clean & maintenance
Clean cover slides

Every two months:
Replace chemical filtration media (e.g. carbon, phosphate & nitrate removers)
Clean pump impellors