Need help with the flow in my Waterbox 4 gallon

[Snuggs]

So I was lucky to win a pico sized tank last December and finally decided to set the darn thing up. Since my hubby LOVES our gsp I decided to give the colony it’s own place. My problem is that the return section drains empty throughout the course of the day. I am using stock pump and filter media with a touch of filter flosswhile I cycle. I suspect the flow through the middle chamber is not correct. Any ideas as to what I should use in that compartment? I was wondering if marinepure would be a good choice . Or will this not let enough flow through

 

[Dom]

I'm not familiar with this particular tank and not sure I completely understand your question.

When you say "the return section drains empty throughout the course of the day", when you power down your return pump, does the return section refill?

In my experience, when the return section on a sump starts to go dry, it is due to insufficient water volume in the system. Is the return going dry before water begins to flow back in to the filter area?