This is just a simple instruction to show you how to clean and maintain your iPhone dive housing after use. The O ring section of this instructable is the most important part.
You can watch the video for the same process.
Step 1: Soak your housing in slight warm fresh water to remove any crystallised sea salt. Room temperature fresh water will do as well if you do not have access to warm water. Soak about 5 to 10 mins.
Step 2: Run the fresh water through the buttons and repetitively pressing the button until the button is clean from sand and dirt. Dry it with a piece of clean cloth
O ring maintenance process
Step 3: Remove the O ring from the housing. Clean the O ring with soap and water to remove dirt and sand.
Step 4: Clean the O ring groove by using a q tip. Run the Q tip in one direction for few rounds until is clean.
Step 5: Apply a small drop of grease on your finger and run the O ring between your fingers until the whole O ring is evenly greased. At the same time stretch the O ring a little bit to check for any crack. You must replace the O ring if there is any crack.
Step 6: Close and seal the housing, inspect for any air bubble along the seal. If you find air bubble, check to see if there are any dirt or crack on the O ring.
Important advice: Always keep the O ring grease at all time. Well maintained O ring will last for a very long time.
FYI, always use proper dive housing equipment for underwater photography even at 5ft of water. Advice not to use any 'claimed' underwater dive zip bags, these products are not as reliable as proper underwater housing.