High Filter Pressure!!

[Bo Dottley]

26,000 Gal in ground chlorine pool with liner. Running a Hayward S244T Filter, 1hp century pump, Hayward CL200 chlorinator.

Been dealing with high filter pressure for the last 2 weeks.

Filter & Recirculate - 22lbs
Backwash & Rinse - 11lbs

Pool jets are very weak - I can isolate each skimmer and have good pull individually but weak when both skimmers and main drain are open.

I have no air leaks on the intake or return lines, that I can tell.

I have a see through pump basket lid, and to the eye, the flow of water coming into it seems weaker than normal.

Actions I have already taken:
1. Changed my filter sand. (1 week ago and backwashed the new sand 3 times for 2 min each time and a 1 1/2 min rinse each time)
2. Installed a new pump.
3. Installed a new chlorinator (the old one looked corroded inside and didn’t seem to drain very well each time I opened it to refill), thought it might have been stopped up.
4. Bought a hose bladder and purged all intake and return lines.

I am lost as to what the problem could be.
Any help would be greatly appreciated.

[Teapot1]

If you are pulling in sufficient water then you have to be outputting the same, water is not deemed compressable at atmospheric levels.
What would really help you is a flow gauge, something like a FlowVis.
Domestic filters generally do not backwash that well so although it will waste a bit more water I would give a longer backwash in oder to try and lift the sand bed, 20% expansion is required to properly clean and sufficient time.
I use an air assited backwash which took a while to perfect but boy does that release the fine clays and dirt that accumulates whilst only using a tiny amount of water compared to water only.
Buy a flow meter and see what you are actually flowing.
A speed controller for your pump may also be a good idea as you only need full speed for backwashing and 99.9% you are in filtration. That would lower the pressure and save both your electricity and new pump.

[Denniswiseman]

Seeing as you have replaced your sand and Filter & Recirculate are the same I wouldn't think that the filter is responsible in this case
All the water goes through the MPV and rinse and backwash are fine. I would take the lid off the MPV and check inside
Take an image of it before so that it can be replaced in the same position
Filter and recirculate both use the pool returns whereas backwash and rinse go to waste. So your pool returns could be your problem

[Teapot1]

Sadly Dennis, this looks like another thread where the author doesn't come back.
From now on I will only answer with thoughtful comment when an OP replies to a standards response. Too busy to have my time taken up by people who are simply there to waste mine.