Aquarium Box Filter - Multi Level

This is an upgraded version of my corner box filter that features multiple stages of filtration. The primary goal of it is to be able to run a sponge along with crushed coral while keeping a low profile. I don't like the look of crushed coral in my tank but I struggle with low pH and buffer, this allows me to maintain my pH long term while keeping my tank looking nice. The bottom level is sized to fit 1 inch sponge. The next level with the slots is made to hold crushed coral. There's a third optional level that can hold additional 1in thick sponge. You can stack as many of the levels together as you like. I recommend printing with a high infill (I use 4 walls and 80% infill) to reduce the risk of it trying to float away. You will need supports for the 2nd and 3rd level inserts, I recommend using normal supports. They come off very cleanly. Things you will need: 1 inch sponge, cut to shape (I used this but any 1in foam sheet should work https://a.co/d/09MyKu2s) Aquarium Co Op easy flow