High pressure reading 2 minutes after backwash

[Vafa]

I replaced my Hayward 6000 DE filter cartridge with new set of 8.
The pool water was green at that moment due to hole in the old filter and I run it for whole night after lowering the PH and adding two pack of shock and 4 chlorine tab without DE!. The gauge reading was 10 right at the start.
Thinking that I will backwash it after getting into some level of cleanness which appears to be wrong idea.
Morning the water was exactly the same color as start and I noticed gauge reading Is 30. Backwashed it several times and run it again and noticed the gauge reading increased rapidly(in a minutes) from 15 to 30 and water flow becomes so low(maybe 20% of regular operation). Also I saw on security cam that pool vacuum stopped moving after one hour which happens when water flow is so low and gauge reading is over ~25.
Backwash decrease gauge reading down to 15 but same story after a minute or two.
Adding 4 lb of DE didn't change anything.
I am about to 1.remove the de filter cartridges and wash off any debris and 2.put it back and run the pump immediately with recommended amount DE solution.
Water flow are same when it on spa mode( spa has a clean new water)
Will that save me from the situation? Or I need different strategy?
The picture taken on first run with new cartridge.
Thanks

 

[JohnT]

Welcome to TFP!

Green water is 100% a chemistry issue. With a DE filter and algae, it can be a very difficult road. The filter is so efficient and the water is so dirty that it clogs very fast. Running the filter on recirculate, assuming that is an option with your equipment, while performing a SLAM Process is probably the best approach. Don’t run the filter without DE as the grids can become clogged to the point where backwashing won’t get it clean.

 

[Vafa]

The pump loose it's prime so fast after back wash I end up with full drain.
since I do that, I will redo the plaster.