Ready to give up....

[BadOleRoss]

As someone else suggested, adding DE to the sand filter will help in filtering out smaller particles.

 

[thepiratemorgan]

Regarding the backwashing, our pool guy told that every time we use the manual vacuum that we need to backwash after. Is this not true?

No that is not true. A slightly dirty sand filter will actually help clear up a pool. I only backwash when needed, using the manual vac or my aquacritter. If my gauge says it's time..5-6 lb rise I verify it by checking to see how strong the water is at the returns. If I feel a substantial lack of water pressure at the eyeball, then it's time to backwash, not before.

Agreed
Keep an eye on that pressure gauge ... great indicator of what the filter is doing.

 

[thepiratemorgan]

Maybe your tired of carrying too many jugs of bleach?
If so, go to pool store (and some big box stores) and buy ONLY liquid shock (10%-12.5% chlorine) that will be less amount of liquid chlorine to carry.
You will adjust the percentage in the pool calculator to what matches what you buy.
Yes, a sand filter does take longer to clear your pool over a DE/cartridge filter.
You have been given great advice from the posters, stay the course as you will see one day it will be perfect!
Keep the pump running 24/7, keep the SWG turned off until done with the shock process, don't backwash as much, NEVER let your FC fall below your shock value CYA/chart, keep brushing pool everyday, try leaving the manual vacuum hooked up and leave down in the deep end for a few hours at a time to help pick up dead algae out of the deep end.
As was stated, your water is no different than our water, it WILL clear up just like ours did when we went through the same thing.

Chuck

My local pool store sells carboy jugs of 5 gal. 12% liquid chlorine for as much as I spend on Great Value Bleach at Wally World. I just don't use it because of the handling and storage. Rather handle a 1 1/2 gallon container. IMO.