Deep cleaning sand filter

I should note that the filter has a clear dome on the top, with the pressure gauge. The multiport is not part of the barrel.

Something like this, but not exactly. Sorry for all the posts.

My pump is a waterco sm600m8 and I can't even get the glass lid off so I think it's time to call a pro in. Might be time to redo the whole thing.

Well, I took a flathead screwdriver to the lid and got it popped open. It actually is setup just like the picture I posted. The sand looked and felt fine to me, I rinsed a good bit of it until all the little bugs and such were gone. I had the multiport set to closed so water was draining down the intake. After I cleaned the pump basket I reassembled everything and went to an immediate backwash. Pressure is reading the same as before which is 10psi, last year when we first moved in it seemed to run at 8psi normally. I wonder if a deeper clean is in the cards, might need to check the laterals? All of this was brought on by an algae attack while we were on vacation, I've come back and treated and tested and all my levels are good, but there is a slight cloudiness to the water still. I thought maybe the filter was struggling, had grooved channels, etc. Anyway, not nearly as difficult as I made it out to be.