Foam Filter Block for FLEX Aquariums

When it's time to improve the water filtration system in your Fluval FLEX fish tank, this Fluval Foam Filter Block is designed specifically for that series of desktop aquariums. It's designed to provide critical stage 1 mechanical filtration by trapping large particles and debris. Suitable for these aquariums: FLEX 15 US Gal / 57 L FLEX 32.5 US Gal / 123 L