If your pool was a bit larger, ideally we would offer suggestion to "SLAM" (link below) to remove potential algae and vacuum as appropriate to remove that dead algae. In your case however, with a pool under 3K gallons and tiny Intex filter, you might find it better to follow the TFP Pool School - Guide for Seasonal/Temporary Pools page. In smaller pools, it's simply more efficient to dump, scrub, and refill as opposed to a few days of SLAMming the pool. Now if you have a small manual vacuum, you could try to vacuum those particulates, but again, it might clog-up that cartridge filter quicker than you can clean it. It's your call really. Consider the options and let us know if you still have questions about either direction you chose. Nice to have you with us.
By performing a "SLAM" (link below). But as I noted above, pools close to 3K gallons aren't always economical to SLAM. It's often just as easy to dump the water, clean, and start over. But if you chose to try a SLAM, you'll also need the proper test kit - either a TF-100 (link below) or Taylor K-2006C. Live algae can't be filtered. Once killed with algae, the dead algae will be filtered.
Put simply, the pump filter cartridge and the vacuum bag have large micron holes (these are not to scale, read the descriptions)
