To all who may find this thread with similar woes. The Reef Octopus Varios-2 fits into the rear chamber of the IM 30gallon long tank. The plumbing for the Reef Octopus pump was kind of annoying but in general I purchased a Y barb fitting that had 2x 1/2inch outlets and 1x 3/4 inch inlet. I then used the two 1/2 outlets to connect to the stock bulkhead outputs of the stock IM 30 and connected the 3/4 inch inlet to the stock barbed Reef Octopus output. It was a pain in the butt since the barbed output did actually taper to 3/4 inch but it would make the connection so tall that it was out of the water in the AIO sump region, therefore I had to ream the 3/4 inch tubing using hot water and a ring mandrel to fit properly and maintain a lower profile. Now the tank has phenomenal flow and is very very quiet. Just a strong note hear is if you want to do this make sure your Apex has a variable speed port, if its the older/cheaper model you will have to buy the VDM module like me which is about 100$.
