Help Modifying A Small Hob Filter!

Hello guys, 
 
I have an idea in my head and need the help of you professionals ! 
 
I have recently come into a LARGE amount of Bio max media and want to utilize it in my 10 gallon as well as my bigger tanks.
The problem being that the 10 gallon is using a Whisper HOB filter with very little room in.
 
I don't want to add a moving bed media filter because they look horrible and the tank is only 10 gallons so it will take  up to much space.
 
 
I am trying to find out if its possible to modify the Whisper HOB and make it flow into a separate (unit / box / overflow) some type of chamber I would attach to the side of it, than pass through the bio max than over flow back into the aquarium.
 
Basically just adding another side chamber to it, so I am hoping someone has done something like this before or can give me some advice or help me put together a plan of attack to knock this out of the park 
 
 
 
 
 
 

Why do you need more media in a small tank? Any filter would cope with stock inside a 10 gallon, It would just be wasting it

Hey Kev, If you havent already, check out "The King of DIY (Aquariums)" and "DIY AQUAPROS" on youtube. They do some pretty good DIY filters (including canister filters) that might give you some inspiration for your project. I think for your project the most difficult part will be re-routing your water to go to the new compartment before going through the main compartment/return. Here's a quick sketch i just did for a pretty easy/cheap mod. (i know it's not your filter but the principles are the same).
 

 
Green: get an additional container for your media
Red: seal the normal flow routes
Yellow: add new flow routes with bulkheads (or something similar) to connect the new compartment to the HOB
Blue: new water flow through new media compartment(s) and back to the old HOB sections.
 
The good part about this type of mod is that it really only costs the amount of the bulkheads used. The downside is that the pumps used in the filters are build to flow as much as they do and extra space between intake and return will probably significantly reduce water flow in your tank.
 
Hope it gives some ideas though!

Techen that is not technically true, it depends on the tank setup and types of fish of course certain fish produce more of a bio load than others no to mention substrate type and thickness and it goes on and on. You can NEVER have to much beneficial qualities  .
 
Vrob, thanks a bunch that is really helpful and the good part is your idea about water flow won't be an issue if you think about it.
 
Once something is filled up with water as long as the outflow does not change the increase in size will not matter.
 
For instance a 5 gallon bucket filled to the top than you put a 1 gallon per mintue intake and 1 gallon per mintue out the 5 gallon bucket can be replaced with a 10 gallon bucket and no difference will be seen the intake/out is still the same just the volume of "holding" water is increased if you get what I am saying.
 
Your sketch was amazing and gave me a decent idea thank you for that I owe ya. 

The other idea I had is whether there is a way to take the motor from the small whisper and just make my own using the AC unit and motor from the whisper? Would save a lot of plastic cutting and what not.