If there are holes in the filter grids, then you MUST replace them. You can find a set of 8 on Ebay for < $150. I think I got Unicel (although Filbur or Pleatco are also fine).
@gearjammer...what is the name of that filter? If AWT wanted to rent one, what would he ask for? Would sludge clog it up fast? Or can It handel super heavy particulate?
In AWT's case, he's not in CA with water restrictions, so in theory could use a trash pump which might be more effective on a sludgy bottom, but he also has a vinyl liner and is rightly worried about water table.
Folks with water restrictions who cant vacuum to waste would love access to something like that, i suspect.