How to visualize a flowchart for the channels?

Question

I'm trying to create a flowchart diagram. It includes the following data:

• Time with interval of 30 minutes
• A group of data for each time interval
• Data flow inside to this group
• Data flow outside from this group

Here is my attempt:

But I think, it's not ok. User can understand which data comes in and which goes outside but it feels like it's so ordinary and not human readable.
What else can I add or change? Should I separate the incoming and outgoing data?
Here is the file.

Answer 1

By the amounts shown in your illustration it looks like the flow of data to outside (red arrows) belong to the intervals previous to where you drew them.

In my attempt, I aligned both flows over and under the main arrow, and added divisions in order to clearly state which elements belongs to each interval, so every interval now has a initial value, flows inside and outside, and a final value which belongs to next interval. If there are more than three intervals (five, ten?) you may want to paint them alternatively with two light colors.

^{download bmml source – Wireframes created with Balsamiq Mockups}