If you clean the cartridge filter in the detergent solution that is normally used to clean it, that should get rid of the algae, but to be sure I'd put back in the clean cartridge while your chlorine is still at shock levels.
Sorry it took so long for an update; I have been really busy recently.
I am pleased to report that I do believe the mustard algae is gone! unkrock:
One warning about the Intex pools, though. The water line in our pool is currently about an inch below the blow-up ring. When I lifted the ring up to vacuum after the shock level began dropping, I found a brown slimy patch hidden in the fold. The chlorine levels were just a bit under shock when I found it and scrubbed it off, so I hope I did not reinfect the pool.
The chlorine levels have been down to normal (keeping it at 8 ) for a couple weeks now, and everything looks great!
Congratulations on getting rid of the yellow/mustard algae. Your experience with the blow-up ring sounds similar to the experience of a user with their pool light as described in this thread. If you still find that yellow/mustard algae comes back if you let the FC level drop below 15% of the CYA level (the normal target is 11.5% of the CYA level with a minimum of 7.5% of the CYA level, but that's for green algae prevention), then that thread indicates that another option for you would be to use 30-50 ppm Borates in the pool since it may inhibit this algae (a regular maintenance dose of PolyQuat 60 may also do the same thing if you don't want to use the Borates).