Need Help Selecting A Canister Filter

[Byron]

I would not bother with old media, but run the new canister alongside the existing filter for a few weeks.  I say this because others will undoubted advise it, but in honesty I have never and would never do this myself.  
 
This is an established tank (I assume this from the initial post, correct me if wrong) so there will be more nitrifying bacteria in the substrate than in the existing filter, not to mention all the surfaces within the tank.  And if you have live plants, better yet.  Provided the tank is not overstocked, we tend to forget that one can shut off the filter completely, and the tank will (or should) manage just fine.  So with that in mind, there is no need to fuss over old media.
 
Three weeks ago I re-set my 70g, with new play sand, and all new filter media (hard media and pads, so a "new" filter in effect).  I left it running for three days after planting, just to make sure I had the hardscape the way I wanted it before introducing fish and then bashing about.  The 100 fish went in the next day.  There were the plants, plus the multitude of bacteria on the plants themselves and the chunks of wood.
 
Byron.

 

[Akasha72]

I'd run them together too ... and once the canister is cycled see if there is space in it to cram in the media from the internal somewhere that way you always have cycled media for an internal should you need it - such as for a quarantine tank for instance. It's what I do now - I have the sponges for my little internal that goes in my Q tank inside my canister ready for use as and when I need them

 

[RainboWBacoN420]

Hey, I picked up the Eheim Classic 600 and it's been running for about a week or so. I noticed when I tried to decrease the flow on the return the valves actually started to leak ever so slightly. But when I let the valves open completely, it stopped leaking. I assume this has something to do with the pressure?
Also, Eheim doesn't have... Entirely clear instructions. Can someone please inform me how to empty and power down the canister safely for maintenance purposes? Thanks!

And I also went ahead and threw a few ceramic rings in the canister, just to give it a slight boost. I see no harm in doing this so I did it anyway.

The return is violent though, all my corys got blown back a bit after turning it on. I decided to take off the spray bar cap and it's a lot better. Although my Gourami isn't much of a fan of the violent exhaust from the return. He has less calm spots to take air from the surface, but I love the nice flow going through the tank, i'd say this is a plus. But some modification will be needed, because the flow is just a bit too strong, and my gourmai only has the left and right side for calm water, he can't stay in the middle or the return will push him away. He doesn't get blown away exactly, the flow is getting pushed off from the intake tube going down the wall of the tank, so the flow is bouncing off towards the middle.