Sand pump valve and cleaning questions:

[Bracks72]

Hello community! Hope your day is going well!

I am selling my house and trying to get me temporary pool that’s setup like a permanent pool clean and operational prior to showing and I am having issues.

Summary: I have a temporary Summer Waves 16’ x 48’ 5212 gallon above ground pool. It used to have a 1500 gallon skimmer plus filter system that I upgraded to a sand filter pump system and setup like a permanent pool. Ran well for 2 years. Due to unforeseen circumstances the pool was improperly closed last season and my pump and sand filter left out in the snow for the winter. I inspected the equipment and found 1 minor issue that I addressed and ran to clean pool unsuccessfully and with an issue with my backwash and rinse water pressure.

Details:
I have disassembled the filter system, taken out the sand, tested the inner piping with no leaks, put in new sand and ran the pump and filter. I found only one issue which was that the filter was leaking water through the backwash. I thought I got really lucky!

I managed to resolve the backwash leak problem by replacing the top part of the valve with a new top (spider gasket and o-ring included) and using the old bottom of the multiport valve which didn’t seem to have any issues. The first problem is that while the leak stopped the backwash is a trickle and the rinse is better but not full flow. Also, I accidentally moved the valve control with pump running once. Seems to have a very small leak out the backwash now but I will see if it continues to do so after letting the system run for awhile. Pictures included in my Dropbox link below. What is the problem and how do I fix it?

Speculating that there may be a clog in the multiport valve somewhere limiting water flow?

Secondly, I went about opening as usual and got most of the leaves and pine out with the skimmer and shocked and threw in arm and hammer baking soda in to clear up the water. It went from brown to a murky teal but no further. Tried a second round of shock and baking soda with no change. The water is too cloudy to vacuum well. The water failed water test strip tests. What is your advise?

Should I blindly vacuum and repeat chemical treatment over and over?

Pool link: https://www.amazon.com/gp/aw/d/B01AUQFA ... asin_title

Pictures link: https://www.dropbox.com/sh/s4dovmqsojf4 ... 4yz7a?dl=0

[Denniswiseman]

You may not have replaced the top of the MPV in it's origonal position. Check with similar MPV's
I would then dismantle the MPV and make sure the spider gasket is seating correctly and nothing is holding it up
Let's have your numbers (CYA is very important) Use a pool store if you don't have a FAS/DPD kit
FC:
TC:
pH:
TA:
CH:
CYA:

Don't blindly add chemicals when you don't know what you need