Many Intex owners are frustrated by the inefficient and complex way the Intex vacuuming procedure is. Having just upgraded to a 22 foot pool, rather than do all the attachments, I used by old Intex pump attaching the hoses and bought a larger vacuum head with brush. I use this instead of the existing vacuum with line you have to use the special attachment to place on the filter (which more often than not popped off). As to the Intex cartridges, I save the ones from the regular usage, after blasting them with the water sprayer on the sink to clean them (I then let them dry and save them for use when vacuuming. I just place the input/output hoses over the top of the pool (I did have to but a longer hose) and as "added" filter on the output used some good old electrical tape and stuffed some old crew socks together and taped them as an added filter over the output...sounds crazy, but not only adds a filter but when you start seeing dirt coming from the sock...time for a filter and sock replacement. I will do a portion of the pool (depending on how much dirt has blown in) and just exchange the filter, again saving it for a later job after cleaning.)
Re-cycling the filters makes it inexpensive and using the second pump is quite easy and the results far exceed the normal technique.
If you overfill your pool you would merely throw the output over the pool BUT watch out for your electrical connections...be sure the hose is far away from them.
I cut my opening pool cleaning time by at least 60% in prep and vacuuming, when necessary is not such a dreaded chore.
Hope this helps someone else.