Black Effluent..

[Guest]

Does anyone know of or have heard of the effluent water from the pump being black??
This just happened today when I turned the pump back on after back washing. This is not black as in debri is coming back into the pool..this is black as in oil, yet it is not oil, although it does have a very slight film to it.
Any help with this would be appreciated, thanks.

[Larry]

I have come across this before. I have seen it happen when either

1. the sand in the sand filter is in need of replenishing/ replacing or descaling, or
2. after clearing up a serious algae problem which tends to result in the slightly slimy film that builds up in the pipes. This film is often dislodged by the increased pump pressure after backwashing.