Poor Pool Suction

[PoolDoc]

Just one suggestion: ditch the CL220. They say a picture is worth 1000 words. Here's one that probably explains why you have high pressure, but low flow:

Hayward CL220 flow path
This unit is a great example of a product that has been successfully marketed for years, in spite of being an outstanding example of "broken by the engineers" design. When you backwash or rinse, you are almost certainly bypassing the CL220. It's possible that you have ANOTHER obstruction in your return piping, besides the CL220 . . . but most likely the problem is just the Hayward unit.