Inadequate turnover rate.
Clean cartridge. Use chemical cleaning of cartridge if necessary.
Run system for longer time or consult dealer or pool service technician.
Partially closed valve or restriction in return.
Open valve or remove obstruction in return line.
Pool chemistry not adequate to inhibit algae growth.
Flow rate too high.
Maintain pool chemistry or consult pool service technician.
Restrict flow to capacity of filter (see filter label)
Cartridge element ruptured.
Air strainer on cap assembly is damaged or missing.
Ensure that cartridge is installed properly. Check for breaks in polyester material. Replace if necessary.
Replace air strainer.
Dirt or contamination.
Damaged or cut O-Ring.
Shut off pump, relieve tank pressure, open air bleeder. Remove tank top and clean O-Ring sealing surfaces. Reassemble tank properly.
Same as above except replace O-Ring.
Obstruction in pump.
Obstruction in suction line to pump.
Disassemble and clean pump.
Clean skimmer basket. Remove obstruction in lines. Open valves in suction line.