Setting up a mattenfilter in sump I finally set up my sump for a freshwater planted tank (https://www.fishlore.com/fishforum/...-gallon-walstad-community-tank-build-out.html) and am very happy with it. It took a lot of research, but in the end, it seems incredibly simple; hard to believe it took so much research to make it a reality. Most sump-related articles and web resources are geared towards salt water aquariums. These sumps can range from simple to overly complicated. I am sharing my setup in case others find it helpful. Please feel free to post questions so I know what topics to expand on. First, I assume you have already done some reading and research. For example, you already decided that a sump is a superior filtration method to canister filters. Not going to try to convince you. To me, its a no-brainer. My 29 gallon sump is HUGE compared to a canister filter… case closed. Also, I assume you know that sumps can overflow, and want to take steps to avoid that. I’ll start with the research findings, and will talk logistics/design in future posts. Subscribe to the thread to get updates. Here's the big picture overview for all you big picture thinkers out there: My filtration goal: super-low maintenance filtration for planted tank. (55-gallon tank) and easier, less stressful water changes for my fish Filtration strategy: 29-gallon sump consisting of Poret foam and appropriate pump/flow-rate to create HMF filter in the smp. Koralia circulation pumps in main tank to ensure lateral flow. Some background: I had Aquaclear 70 with QuickFilter as the “prefilter” to clean out small debris and keep water crystal clear. It worked, but the QuickFilter clogged after about a week, and had to be replaced weekly. Some may consider this “underfiltered” for a 55 gallon tank, but it worked for me given that my tank was heavily planted. Not sure the filter did much biofiltration, I am pretty confident my plants did most of the biofiltration. Changing out the QuickFilter was messy, and was getting expensive to replace weekly. I want to increase the stocking level so wanted more filtration as well as more water volume. Also, I wanted to lower stress to my fish during water changes; wanted to premix the chemicals, equalize the water temperature, and not have to worry about freaking the fish out during water changes. Summary of theory/research findings: Filter media. After extensive research, I decided that a Hamburg Mattenfilter (HMF) was the way to go. These are basically very large sponge filters with a particular flow rate to optimize bacterial filtration. No need for bioballs, etc. Just a couple of sheets of Poret foam that last forever and can go 12 months between cleanings. There are knockoffs and cheaper options out there, but I choose German engineering over Chinese knockoffs anyday, so I went with the Poret foam from Swisstropicals.com. Breeders and hobbyists typically use these foam sheets in the tank itself, either at the end of a tank, or in the corner, as a corner filter, but I didn’t want that. It’s even easier to maintain in the sump, and it won’t make the tank look ugly. For the “definitive” reference on mattenfilters, I would check out www.deters-ing.de/Filtertechnik/Mattenfilter.htm Use Chrome and google will translate it from German to English for you. The key issue here is getting a good flow through the filter to achieve the HMF filter effect. Too fast flow, and you won’t get all the benefits of a mattenfilter. Too slow, and you won’t be pushing enough water through the filter to be an effective biofilter. The equation is shown here: http://www.deters-ing.de/Filtertechnik/Glei-V.gif (I’ll post an example for my sump later). Sump plumbing. Drilling the tank wasn’t an option for me (tempered glass in the Aqueon 55 gallon tank). I decided against a DIY PVC overflow due to risk of flooding. I wanted to see the water flowing over the tank wall, and PVC pipe wouldn't let me do that. I instead bought a eShopps 1100 Overflow box, the one with two 1” return lines and clear U-tubes so I can see the water flowing over the tank wall (and any accumulating bubbles, if any). The two return lines were a must for me. I use one as an emergency overflow, as in a Herbie design. For more info, checkout http://gmacreef.com/herbie-overflow-reef-tank-plumbing-method-basics/ Personally, I think a BeanAnimal design is even better in a coast-to-coast weir, but I couldn’t drill the tank for three bulkheads. The eShopps Overflow box had a max of two bulkheads. Stil, two is enough for a Herbie design, which when properly setup is pretty safe and QUIET! I have the sump running now, it is really QUIET, too quiet, actually. I changed the flow so I would occasionally hear some noise… LOL. That way I know that (1) it's working. (2) hasn't flooded my living room yet. Here's a picture of the sump while I was testing the flow: Flow. Two words: lateral flow. more info later (need to dig up my bookmarks and find the good links. Good info on properly flow is surprisingly hard to find on the net, lots of misinformation out there). Also, the sump pump isn't the main source of flow in the tank. Use circulation pumps in the main tank to boost flow, and make sure to get the sump pump to hit the properly flow rate to achieve HMF/biological filtration. Ok, more info later, feel free to ask questions so I know what to expand on!