DE enters pool on pump start up (but only when on low).

[IsThisWhereIPutMyName?]

Hi there - great forum here. I'm hoping someone can point me in the right direction.

I have one of the simple model Hayward DE filters (bump on top, fingers inside and no multi port). I run it with a 1.5 HP Pentair dual speed pump from a single skimmer to a single return jet. It's an above ground pool.

I've found that when I turn my pump on if it is set to high, everything is normal. When I set it to low and turn it on I can see a dirty cloud coming out of the return vent. It's a mix of white (I assume the DE powder) and chunks of sediment. If I set it to high to turn on and switch to low without stopping it's fine.

I've broken down the filter twice and I don't see any damage anywhere. I think somehow the filter needs a certain pressure to seal and work properly. My pressure readings are basically 0 when on low, 10 when on high and 20 on high running thru 2 4x20 passive solar.

I've been running it mostly on low for 1.5 seasons without an issue. Any ideas on what to look for the next time I break it down? Could I be doing something wrong when putting the top back that misaligned it? I'm at a loss...

Thanks.

 

[duraleigh]

What happens when you start on high and then switch to low?

 

[IsThisWhereIPutMyName?]

Starting on high and switching to low seems ok as long as the pump keeps running. Starting on high, stopping the pump and then turning back on with low quickly is really bad.

 

[IsThisWhereIPutMyName?]

So I need to make a slight edit after paying more attention today. Even on high there is sediment coming out on startup. However on high it seems like there is less and it doesn't take as long to clear up. It is definitely only on startup - if I run the pump 24/7 there is no problem.