Thank you Ben, I've finally got crystal-clear water as long as I let the dead algae settle out over a 24 hr period, and it's now only in patches covering about 20% of the bottom after a third vacuum-to-waste...I think at this point, a better quality filter cartridge will get this stuff out, once put into suspension with some pool activity. I'll use the link you recommend. You know, it's funny, I read Amazon reviews of folks really happy with the Intex originals because they last so long before needing to be changed.....well, duh!, that's because they don't filter well!