For those of you that have diatomaceous earth (D.E.) filters on your pool, here is an example of a torn grid. This was pulled from a filter that was caked full of D.E. For some odd reason this was the only one that was ripped, but it was heavily damaged. If you notice powder or dirt blowing through your jets upon starting your pump, while vacuuming or when you add DE powder after the backwash cycle you may have a ripped grid or two.
These grids should last 4 - 5 years before needing replacement. To keep them in good working order you should backwash as necessary. For further instructions on how to do this, see DIY Pool Care Step 8.
Once a year you should have your tank taken apart and cleaned. Over time the D.E. packs in tight and the grids need to be hosed out and degreased.
Adding the proper amount of D.E. is essential to keep your filter functioning properly. I cannot tell you how many times I have talked to inexperienced pool owners who never knew you had to add D.E. powder. Without it the grids will get caked with oils and gunk only to be ruined prematurely.
With our company expect to pay for an $94.99 service call along with $20-$30 per grid depending on your filter size. Many filters have 8 grids in them. Usually when 50% are damaged DE filter grids we recommend changing all of the grids out. It will cost less in service calls and save you hassle because of the other grids breaking apart shortly thereafter.