While on filter, water is filtering and backwashing


New member
Jul 5, 2018
Beaumont, TX
I have a DE pump. The spider gasket on port was recently replaced. All filters in pump were replaced.
Everything was working well a day ago but now the water, while on filter, is filtering but also “backwashing “
I did have a service put in “wrong” spring on port but, according to him, it only changed the positions of the operations. And, until a day ago, it was working okay.
Also, is it okay to have the gauge on half skimmers and half bottom drain while filtering? Thanks for help.


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40

Sounds like your MPV valve is not re-assembled correctly or the gasket has failed in side of it. Read the article above for ideas.

Your valve setting for skimmers vs main drain can be 90+% skimmers. Just enough from the main drain to move the water in the pipe. Them main drain does essentially nothing in keeping the water clean, etc.
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