Can find cause of all the dirt/sand in the pool

[matt4x4]

Nicole, a filter can usually be set to "bypass" or "whirlpool" which will essentially do the same as emptying your sand out of it or removing the hoses to bypass it.
Duraleigh is onto something with the spider gasket.

I can tell you right now, you don't need a cracked lateral for this fine dirt to make it through a sand filter, laterals have relatively large openings in them in comparison to the dirt you are getting, if you had a cracked lateral, you would be getting sand in the pool too - cracked lateral is likely a non issue.

When you add the DE, have you looked at what comes out of your return within the next 5 minutes? If your return starts to eject cloudy water, then the DE is getting into your pool either by pushing through the sand (uncommon) or by way of a bad spider gasket.

When you set your filter to backwash or rinse, do you feel anything coming from the return? If you do, it's a sign of a bad spider gasket.

How far up did you fill your filter with sand? Just wondering if it's over full - this can also have negative effects.

Last but definitely NOT least, since this problem started after adding new sand, logic tells me the problem IS THE SAND ITSELF. Open the filter, grab a handfull of sand and spread it out on a paper towel, if it starts to dye your paper towel brown, it's the sand. By now, the finer particles may have settled towards the bottom of the filter, so if you can get a sample from further down it would be beneficial. Remember to backwash first so you're not grabbing dirty DE mistakenly.
If it's the sand, replace with Zeobrite or Zeolite - IMO - a great product.

Part E has to be disassembled - unbolt all bolts around the top ring, it should come appart vertically (probably also have to remove pin for handle and remove handle before it will lift appart.).