Thanks for the help Waste!

I used your DE thread to help me do a better job just changing the DE, rather than opening up the filter and really cleaning it (I'll never understand why the only cap they could come up with has 30 bolts). Now it's at least in much better shape. It still builds pressure after a couple of hours and needs a bump, but at least the water flows a lot better.

Current state of the pool is a very cloudy blue (can't see bottom in deep end, and can only just see it in shallow) with 95% of the algae gone. Been that way for a day or two now. But, I've shocked it everyday to raise the CL to at least 15 ppm and the next day it's all gone, so something is getting killed in there. The rest of my levels are good, so I don't think anything else is eating up the CL.

Thanks again for the help!