Hi,
After a long weekend, some important updates (and realizations) have been made:
1. We changed the sand in the filter.
2. I noticed the (defective) pump gauge showed 10 psi when it was off. So, the actual psi was 15, not 25.
3. Had a great pool party, in spite of the still cloudy water. (Tested ok enough to swim, fyi.)
4. Realized that we had been running the filter on the wrong setting so the water was just circulating instead of going through the filter sand...duh!
5. Added more bleach and DE.
6. Looking MUCH better already!

It is ironic that I have been doing so much research and testing, when most of the problem should have been obvious! Thank you for your patience and help. I am hopeful that the crystal clear sparkling water is just around the corner