Looking to set up a sump or refugium under your aquarium on the cheap? DIY’ing aquarium equipment can be a fun and educational experience, but be careful with the type of products you use, as their original intentions were not for aquarium use. Things like Rubbermaid containers make for great sumps, but their thin plastic bulges as they are filled with water. For short-term use, this bulging may not be an issue. Unfortunately though, this plastic has a tendency to crack and become brittle with prolonged use. These usually lead to total sump failure, causing water to get everywhere and forcing you to rebuild, hopefully with different materials this time.