Mustard Algae Appears ONLY When I Run the Pump!  My chemicals are good; checked with a pool strip.  My pool's water will not have any brown-colored algae on the floor for at least 4 days as long as I don't run the pump.  Once I run the pump - whether I add liquid shock or use broadcast shock - there will be brown-colored algae on the floor the very next day.

Please help me figure this one out.

Thanks!