When the pump kicks on after being off for some time, the DE particles and the dirt particles that were laying at the bottom of the filter tank are now racing back up to the grid fingers - correct? But in doing so, some of the dirt passes thru the fabric before the DE does a complete re-coat. So maybe this filter has an inherent design flaw and it's been doing this blowback since day one - but i have only noticed it recently when i walked past the returns after i activated the pump?