API Nitrite Test Kit Brightwell It is also separate from

It is also separate from the smaller gasket located beneath the air-filter cover

or no longer producing proper flow

Threaded Strainer Fitting (2 Inch) is a large black threaded strainer for high-flow aquarium

Check each joint after assembly to make sure it is fully seated before running water through the return line

and if of similar size

API Nitrite Test Kit Brightwell It is also separate fromAPI Nitrite Test Kit API Nitrite Test Kit is a freshwater and saltwater liquid test kit that measures nitrite from 0 to 5 ppm, helping aquarists monitor cycling, biological filtration, and invisible water problems that can harm fish. API Nitrite Test Kit for Freshwater and Saltwater Aquarium Cycling Nitrite is produced as part of the aquarium nitrogen cycle and can rise when fish waste, uneaten food, or biological filter imbalance affects water