I installed a temporary filter last year, made out of a plastic truck box. It started to bow under the water pressure and had irregularly shaped sides. Time for a new one. It needed to be sturdy and have room for all four sheets of Matala filter material. I built the box with treated 5/8" plywood. It's about 6 feet long. The depression in the bottom is for the drain. 3 layers of fiberglass and resin with 2 gelcoat layers. Covered in fiberglass, sanded and fittings installed. I removed our temporary stairs and got all the plumbing done. First time that I finished a project without needing a second trip to Home Depot for fittings. Added the Matala fitlers (4 full sheets) and turned it on. No leaks!