Help With DIY 20g Sump

I just completed the build on a 20g long sump/refugium for a 65g DT. I’m using a Glass-Holes 700 kit for the drain and a Mag 7 for the return pump.

The sump was recommended by 2 reefers at a LFS through an independent review. The 3 compartments will be used this way:

Section 1: live rock rubble
Section 2: microalgae
Section 3: return

The bottom baffles are 7". The baffles top-down are 10". This allows just over 1.25 inches off the tank bottom and 1" spacing between the baffles contained in each set.

The first set of baffles is to separate the rock from the microalgae and, the 2nd set of baffles act as a bubble trap and to create the return section.

But in testing it today, I'm troubled with the water flow from the 1st section and middle sections of the sump, because it appears that the water flow is suggestive of a much higher circulation near the water line and seems not to encourage circulation throughout the middle section. So I’m questioning the ultimate effectiveness and efficiency of the refugium. Otherwise, from a return and drain design, it seems okay.

The only method I could conjure up to test my “poor” water circulation theory was to place a tiny piece of pink plumber’s tape in the 1st section and watch it flow through the 1st set of baffles, etc. - thinking the tape light enough to mimic what travels with the water (but not sure the tape is the best media to use.)

Two problems were immediately obvious:

1) The tape (1/4" strip) needed to be coaxed near the bottom of the 1st baffle before it got sucked through into the 2nd section. Otherwise, it just hung out meandering here and there... in the 1st section. Which then had me questioning flow from section one to section 2. :-(

2) Once in the middle section of the sump, the tape immediately floated to the top and went nowhere. It just hung out. :-(

Comments on the design; feedback on my methods or whatever are welcomed and will be greatly appreciated. Photo below:
Sump Build 20g Long pictures by LarryPhoto1 - Photobucket

 

Nice build very clean. Please poast pics when you get it filled with rock and macro algia

 

Thanks! For a first effort, not so bad although I thought it could have been more cleanly done.

Anyway, just not sure that I am getting the best flow with this design.