There's some good options for DIY media for sure. I know the problem I've run into with my somewhat recent (non AquaClear) HOBs purchases was they were smaller HOBs, and trying to retrofit them with DIY was difficult because of the small size of the filter housing. Stuffing anything other than the OEM cartridge in there would totally change the flow path of the water being filtered.

Imagine makes the clamshell cartridges that fit Emperor, Penguin, and Whisper filters. So it's less DIY than it is adopting something designed to fit. I use the blue sponges that come with the clamshell cartridge and only diy the blue bonded and micron pads, cutting them to fit the clamshell. I am able to run four of these in and Emperor 400 or Penguin 350. Two in a Penguin or Emperor 250. The fit just like the stock cartridges.

Oh that is VERY cool. I didn't know those re-usable filter clamshells existed. Definitely makes a cartridge HOB way more attractive.

Emperor 400's uses to be $40. In Canada they went up to $80, I don't know when or if its increased in price anywhere else, but man does it suck. I had them running on my 125 for two years with no issues, so i decided to buy another one for my 55 and it was $80.. crazy.

I've also had both Emperor 400 and 2 AC 70's... I like the AC much better. (quieter, easier to maintain, better quality) IMO.

Maybe if one of my emperors breaks down I'll try one, I see lots of people have them with oscars.

Same here I have emperor 400's , I like them and fill the grey plastic cases with blue filter pad cut to fit and use foam pads for my fluval ( generic pads from amazon) in front of the grey case as extra filter . It works well, they were loud at first but have since gotten much quieter over time. I'll keep them till they go out , then try the AC or penguin.

I use AC 70s on my water aging tanks because it's easier to remove and replace media such as Peat and Carbon. But on my tanks with fish I use Emperors and Penguins, because it's easier to clean or replace mechanical media.

I simply cannot justify the increased cost of an AC110 over an Emperor 400. If I am going to spend that much on. Filter it's going to be a canister.

Agreed!

like someone else stated, the bio-wheel on my emperor would always stop moving & a bit noisy.