55g DIY Background Plumbing Help - My backgrounds carved but now i need plumbing I'm looking for ideas on how to make best use of my canister filter and additional pump given my background design. I have some ideas below but would really love some experienced opinions before I start cutting. Thx Quick background: Had a 6 Gallon Fluval for a couple years, finally got a larger place so I could move up to a 55g. Picked one up on craigslist, grabbed some foam and Drylock and went to work on the custom background. Here we are a few days later and I want to get some advice on plumbing. I feel I have a decent strategy but would rather get some informed opinions prior to cutting up my newly created background. 55G Long Eheim EccoPro 158 GPH Additional Pump 300 GPH Use: Community Freshwater 78 degree type fish (i.e. Guppies, Tetras, Cories, Bristlenose Pleco, Honey Guaramis, Khuli Loaches, Shrimp, etc) Fully stocked eventually but will add the species slowly starting with my out of control guppy population who will eventually be kept in check by some larger fish. Per the images below I intend on carving out a large cavity in order to house my Eheim intake, Additional Pump and heater potentially (might go inline). The idea is to create an intake cavity which will be separated from the main tank by a course removable filter sponge. The top of the rock will attached magnetically so it will be removable for swapping sponge and servicing. The theory is that my Eheim will give me it's recommended 2-3 times biological filtering per hour and the cavity itself will provide a total of around 10 times mechanical filtration per hour. From what I have read, this should provide an adequate array of filtering. I would like to have at least two outputs at the top on the side "small triangle rocks". This will be upward facing for surface agitation and as of now running off the 300GPH pump. I am also thinking of an under-gravel jet type system (although more resembling a spray bar) to distribute my Eheim return from the bottom of the tank. I will simply be matching the number and diameter of holes in an Eheim spray bar to hopefully get close to optimal results. These 8 holes would be evenly spaced around the front and sides of tank to discourage dead spots and encourage water flow towards the center fed intake chamber. I am not necessarily trying to move the detritus but just encourage full circulation. My python should pick up the scraps. Anyways, that's the basic gist of what I have conjured up in my head but before I start carving out for plumbing I wanted to get people's inputs on what they would do in this setup and specifically with the output flow. I am open to rerouting and or splitting the inputs to any of the four spots marked on the top of the BG and the under-gravel spray bar. At the end of the day this will be fairly permanent so I would like to make sure I consider all options before finalizing the design. P.S. This thread is strictly about plumbing for now but I will be more than happy to share the background build at a later time. I know I read a ton of different ideas and styles and I think it is helpful to have those types of threads available.